Piki, Aggressive Student

{2}: Target Creature gets +2/+0 until end of
turn.
At the beginning of your upkeep, if you control
4 or more creatures with power greater than or
equal to 3, transform Piki, Aggressive Student
into Piki, Master Warrior. (Exile Piki, Aggressive Student and return it to the battlefield as Piki, Master Warrior.)