Rabid Morphling

Rebirth counters are not removed from Rabid Morphling when placed in a player's graveyard.
{t}: Put a rebirth counter on Rabid Morphling.
{b}{b}: Remove {x} rebirth counters from Rabid Morphling. Return Rabid Morphling to the battlefield as an exact copy of target creature
where {x} is equal to or greater than the converted casting cost of that creature.