Killer Queen

Enchant Kira, Yoshikage - At the beginning of
combat on each turn, Killer Queen becomes a
creature, with haste and unblockable except by
Spirits. At the end of combat on each turn,
Killer Queen becomes an aura and attach it to
Kira, Yoshikage. When Killer Queen deals combat
damage to a player, put a Bomb! counter on a
non-land permanent that player controls. For as
long as a creature has a Bomb! counter, it gains,
"when this creature deals combat damage to a
creature, destroy both creatures"