Evolved Spinoderm enters the battlefield with four oil counters on it.
Evolved Spinoderm has trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
as long as it has two or fewer oil counters on it. Otherwise, it has hexproof (This permanent can't be the target of spells or abilities your opponents control.)
At the beginning of your upkeep, remove an oil counter from Evolved Spinoderm. Then if it has no oil counters on it, sacrifice it.