Disposable Learner Device (MP21-EN027) [2021 Tin of Ancient Battles]

The equipped monster gains 200 ATK for each monster in your GY. During the End Phase, if this card is in the GY because it was sent there from the field this turn: You can Set this card, but banish it when it leaves the field. You can only use this effect of "Disposable Learner Device" once per turn.