From DominionStrategy Wiki
Trash up to 2 cards from your hand. If you trashed at least one, exchange this for a Vampire.|
(This is not in the Supply.)
Bat is a Night card from Nocturne. A Bat is what a Vampire turns into when you play it, and so one function of Bat (from a game design stand point) is to prevent you from playing your Vampire too often. Bat is a trasher, and the only way to get your Vampire back is by trashing with Bat.
- The Vampire is put into your discard pile.
- If there are no Vampires in their pile, you cannot exchange Bat for one, but can still trash cards.
Refer to the Vampire strategy section.
|Trash up to 2 cards from your hand. If you trashed at least one, exchange this for a Vampire. (This is not in the Supply.)||Nocturne||November 2017|
Other language versions
Bat and Vampire are the only cards that exchange when played.
Of course there had to be a Vampire, and of course it turns into a Bat. That's what they do. Well vampires do tons of things, but that's one of them, and you can only capture so much in a Dominion card. Vampire gains you cards and Hexes people, while Bat is a trasher, and has to feed to turn back.
Bat started out an Action, but people demanded that it be a Night card too. For a while it was a Duration card, that drew you a card if it didn't turn back. That made it not so bad to have late-game Bats stuck in your deck. Mostly Bat could trash a card, and whether or not you got your Vampire back depended on what you trashed. Later it could trash two cards and cared about how many, settling on "at least one." It didn't want to automatically turn back, but didn't want that to be difficult either.