Or do something like:
Fatebleeder

Creature - Elemental Leech

: Deal 1 damage to target [creaure or?] player. If that damage is delt to a planeswalker, put two +1/+1 counters on Fatebleeder and untap Fatebleeder.
If Fatebleeder has two +1/+1 counters, it gains +2/+0 and flying [or shadow I guess].
When a counter is put on Fatebleeder if it has six or more +1/+1 counters on it, sacrifice it.
0/2
At worst its a 0/2 pinger that costs 2 mana per ping. At best hes a 4/4 or 6/6 flyer.