Carcinisation

{2}{t}: Put an evolution counter on target
creature. This ability cost {2} less if you control
at least 5 crabs.
If a creature has at least one evolution counter
on it, it is a blue crab instead of it's other types
and colors.
If a creature has at least two evolution counters
on it, it has base power 0/2 and looses all
abilities.