Sanskrit -- "Thus-Come One" or "Thus-Gone One". Epithet of a Buddha, particularly the Buddha Shakyamuni.
A 'brief' teaching:
The Coming and the Going of Tathagatas
Dharmodgata: Tathagatas certainly do not come from anywhere, nor do these go anywhere. Suchness does not move, and Tathagata is Suchness. Non-production neither comes nor goes, and Tathagata is non-production. One can conceive of neither coming nor going of reality-limit, and Tathagata is reality-limit. This same can be said of emptiness, of anything which exists in, or according to facts, or of dispassion, of stopping, or of the element - space. Tathagata is not outside these dharmas. Suchness as these dharmas is Suchness as any and all dharmas, and Suchness which Tathagata is and is intimate with through realization, is simply Suchness as any and all Tathagatas. Here, there is no division within Suchness. Simply put, before even the idea or number 'one' as some form of singularity, throughout and after all is Suchness. Such is neither two, nor three, nor one divided into many. Suchness does not even pass beyond counting, as it can not be counted either subjectively or objectively to begin with and thus, certainly there is nothing anywhere to end with. Neither is Suchness one, nor other than one by which to determine any singularity, nor two nor three nor apart from these. Nothing of or by any concept whatsoever can Suchness relate to or be related to, yet Suchness is greatest of anything conceivable and infinitely beyond even this...all form or formless experience(s).
A man, scorched by the heat of summer, during the last month of summer, at noon might see a mirage floating along, and might run towards it, and think "here I shall find some water, here I shall find something to drink." What do you think, you children of good family, does this water come from anywhere, or does this water go anywhere, to or from the Eastern great ocean, or the Southern, Northern or Western?
Sadaprarudita: No water exists in this mirage. How can its coming or going be conceived? This man again is foolish and uninformed as, on seeing the mirage, he forms the idea of water, as here is no water. Water in its own being certainly does not exist in that mirage, any more than merely in his thought that it does.
Dharmodgata: Equally foolish are any and all these who adhere to Tathagatas through form and sound, and who in consequence imagine coming or going of any or all Tathagatas. A Tathagata can neither be seen nor determined from any form body. Dharma-bodies Dharmakaya are such Tathagatas, and the true nature of dharmas neither comes nor goes. Here is no real coming or going of the body of an elephant, horse, chariot or foot-soldier, tree or even a rock, which has been conjured up when magicians perform. Just so, here is neither coming nor going of Tathagatas which, as with all things, neither have any granting given nor even, any conjuring whatsoever. A sleeping person might in dreams see one Tathagata, or two, or three, or up to one thousand, or still more . On waking up, however, they no longer see even one single Tathagata. What do you think, dear children of good family, have these Tathagatas come from anywhere, or gone to anywhere? As Tathagata means 'one thus gone', in this relative sense in so doing one cannot thus come. But, what's not too frequently understood, is that Tathagata also means 'one thus come', and likewise in so doing can one not be thus gone. Yet, such is this fact in principle and truth, that in, or as Suchness Tathagatas neither come nor go, at once within and throughout these three times...and at once here stand on naught but pure undifferentiated awareness as space outside of and through any and all dharmas. Such is this difference of purely equanimous stance the same as this fathomless station of all dharma.
Sadaprarudita: One cannot conceive as in any dream any dharma whatsoever as having the status of a full and perfect reality, for any dream is deceptive.
Dharmodgata: Just so Tathagatas teach all dharmas are as a dream. These who do not come to naturally and wisely know all dharmas as these really are, which is to say, as a dream, as Tathagata points out, these adhere to Tathagatas through their name-body and form-body, and in consequence these imagine Tathagatas come and go. These who in ignorance of true nature of dharmas imagine a coming OR going of Tathagatas, these are just foolish common people...not as yet diligent to truth, and presently as is as good as any and all times these belong to birth-and-death with six places of rebirth, and these are far from these revelations of perfection of wisdom, far away from dharmas of a Buddha - yet experience these dharmas within each and every breath, as close as pure life itself.
On the contrary, however, these who know all dharmas as a dream, i.e., as they really are, are in agreement with the teaching of Tathagata, these do not imagine the coming or going of any dharma, nor its production or stopping. These naturally know Tathagatas true nature, and do not imagine coming or going of Tathagatas. And these who naturally know true nature of Tathagata, these course near to full enlightenment and these course in this perfection of wisdom. These disciples of Lords do not consume alms fruitlessly,  and these are worthy of the world's results and dedications. The gems which are in the great ocean do not come from any place in the East, or West, or any other of the ten directions, but these owe existence to wholesome roots of beings. These are not produced without cause, or, are not without cause to be produced. Such simply manifest due to these causes and conditions. Yet still, as dependent on cause, condition and reason, these gems are coproduced and stopped by conditions, these do not pass on to any place anywhere in the world in any of the ten directions. And nevertheless, as these conditions exist, the gems are augmented; as these conditions are absent, no augmentation takes place. Just so the perfect body of Tathagatas does not come from any place anywhere in the ten directions, and it does not go to any place anywhere in the world with its ten directions. But the body of Buddhas and Lords is not without cause. It is brought to perfection by conduct and action in time, and it is produced dependent on causes and conditions, coproduced by subsidiaries, produced as result of karma done in this past. It is, however, not in any place anywhere in the world with its ten directions. But when these conditions exist, the accomplishment of the body takes place; when these conditions are absent, the accomplishment of the body is inconceivable.
As the sound of a boogharp is being produced, it does not come from anywhere. As it is stopped, it does not go anywhere, nor does it pass on to anywhere. But it is produced conditioned by this totality of causes and conditions for it to occur, -namely the boat-shaped hollow body of the harp, the parchment sounding board, the strings, the hollow arm of the boogharp, the bindings, the plectrum, the person who plays it, and this person's exertions and coming to knowledge of the music to be played thereon.  In this way this sound comes forth from the boogharp, dependent on causes, dependent on conditions. And yet that sound does not come forth from that hollow body of the harp, nor from the parchment sounding board, nor from the strings, nor from the hollow arm, nor from the bindings, nor from the plectrum, nor from the person who plays it, nor from this person's exertions OR knowledge. It is just the combination of all of these which makes the sound conceivable. And as it is stopped, the sound also does not go anywhere.
Just so the perfect body of Buddhas and Lords is dependent on causes, dependent on conditions, and it is brought to perfection through exertions which lead to many wholesome roots. But the augmenting of Buddha-body does not result from one single cause, nor from one single condition, nor from one single wholesome root. This is also not without cause. This is coproduced by a totality of many causes and conditions, but does not come from anywhere. So, also as this totality of causes and conditions cease to be, this does not go to anywhere. Thus is viewed the coming and going of Tathagatas, and this conforms to true nature of all dharmas. And it is just as this is naturally re-cognized as Tathagatas, and also all dharmas, are neither produced nor stopped, you are fixed on full enlightenment, and you definitely course in perfection of wisdom and in skill in means.
As this disquisition of the fact Tathagatas neither come nor go is being taught, the earth and the entire great trichiliocosm shakes in six ways, stirs, quakes, gets agitated, resounds and rumbles. And all the realms thought to be and seen as of Mara are stirred up and discomfited. All the grasses, shrubs, and herbs and trees in the great trichiliocosm bend in the direction of the Bodhisattva Dharmodgata.  Flowers come up out of season. From high up in the air a great rain of flowers comes down. And Sakra, Chief of Gods, and the Four Great Kings scatter and pour heavenly sandalwood powder and heavenly flowers over the Bodhisattva Dharmodgata, and say: "Well spoken, son of good family. Through your might we hear a sermon which issues from ultimate reality, which is contrary to the whole world, and which gives no ground to any beings which are established in any of the views which involve the assumption of an individuality, or have settled down in any of the views which assume the existence of something which is not."
Sadaprarudita now asks Dharmodgata: "What is the cause, what is the reason why this great earthquake is manifested in the world?"
Dharmodgata: In consequence of your asking for this disquisition on the non-coming and non-going of Tathagatas, and through my exposition of this, eight thousand living beings acquire patient acceptance of dharmas which fail to be produced, eighty niyutas of living beings raise their hearts to full enlightenment, and of sixty-four thousand living beings the dispassionate, unstained dharma-eye is purified for vision of dharmas.
Sadaprarudita's Self Sacrafice
The Bodhisattva Sadaprarudita now has a supreme, most sublime feeling of zest and joy: "It is a gain to me, a very great gain by asking for perfection of wisdom, and for this disquisition, I have wrought the weal of so many beings.  This alone brings me merit sufficient for the accomplishment of full enlightenment. Unquestionably I become a Tathagata." In his zest and joy he rose seven palm trees high into the air, and, standing at the height of seven palm trees, he reflected: "How can I, standing here in the air, do honor to the Bodhisattva Dharmodgata?" Sakra, Chief of Gods, now sees him, and reads his thoughts, presents him with heavenly Mandarava flowers, and says to him: "Honor the Bodhisattva Dharmodgata with these heavenly flowers! For we feel in this we honor the man who helps you. Today your might wroughts the weal of many thousands of living beings. Rare are the beings who, like you, have the strength, for the sake of all beings through countless aeons to bear such great burden." RWB