Bat Signal

When Batsignal enters the battlefield, put
1 "CALL" counter on it.
During your Upkeep step add 1 "CALL" counter to
Batsignal.
{t}, destroy Batsignal: Search your library for a
Vigilant creature with a total mana cost equal to
the number of "CALL" counters on Batsignal.
Put it on the battlefield tapped.