shape shifter wurm

at the beginning of your upkeep you may choose shapeshifter wurm become one target card that says wurm on it
this abilitie is still on this creature if has transformed
{u/b}{u/b}{u/b}{u/b}{u/b}{u/b}{u/b}{u/b}{t}this creature becomes target permanent in your deck
one second it is a mouse and the other second it eats you up as a giant wurm