The Radiance

Bossfight (When this creature is dealt combat
damage, put it and attacking creature in the Arena,
where blocking damage and healing don't apply.)
Creatures with Bossfight you control gain
+X/+0, where X is half the damage they have
taken, rounded down.
{x}{3}{w}{b}{r}: Creatures with Bossfight you
control get X +1/+1 counters.