Rabbit Hole

Hidden Realm (At the beginning of each endstep, a creature you control can enter or leave this card's
hidden realm.While it is in the hidden realm, it is
treated as though it doesn't exist. It doesn't leave the
battlefield)
Whenever a creature leaves this card's hidden
realm, you may have target creature have a base
power and toughness 1/1 or 4/4 during the next
turn.
"Where on earth could the little dear have been? And
where did she find such delicious snacks?"