Sisay and Gargos

Sisay and Gargos enters the battlefield with X
+1/+1 counters on it.
Sisay and Gargos gets +1/+1 for each color
among other legendary permanents you control.
Whenever this creature becomes the
target of a spell, search your library for a
legendary permanent card with mana value less
than Sisay and Gargos power and put it onto the battlefield.