Plucky Hoodlum

This creature is a Hero
Skulk.
Level Up - Prowess (Whenever this creature deals damage or is dealt damage from a source an opponent controls, place a level counter on it)
Level 1 - 1/2 Skulk, first strike.
Level 2 - 2/2 Skulk, first strike
Level 3 - 2/2 Skulk, double strike
Level 4 - Transform Plucky Hoodlum (Sledgehammer Assassin)