Shoreline Scavenger

Evolve (Whenever a creature with a greater power or toughness than Shoreline Scavenger enters the battlefield, put a +1/+1 counter on Shoreline Scavenger.)
At the beginning of your upkeep, you may remove all +1/+1 counters from Shoreline Scavenger. If you do, put that many +1/+1 counters on it at the beginning of the next end step.