If the revealed development is a unit that cannot be in play (such as a Hero card in a zone that already contains a Hero), the effect of the card is cancelled immediately, and the development is flipped face down again.
这个我下的官方1.4里写的是
if the revealed development is a unit that cannot be in play(such as a hero card in a zone that already contains a hero)
,then the unit that caused the illegal state to occur is immediately sacrified
