Unseen Rat

Skulk, Swampwalk, Forestwalk
When Unseen Rat enters the battlefield target creature you control gains landwalk until end of turn. Other creatures you control have Skulk.
{b}, Pay two life: Target rat you control becomes unblockable until end of turn.
Ninjitsu {2}{b} ( {2}{b}, Reveal this card from your hand, return an unblocked attacking creature you control to its owner's hand: Put this card onto the battlefield from your hand tapped and attacking.)