Beckett, Anxious Guardian

Whenever a creature enters the battlefield under
an opponent's control you may pay: {2}{b} Put a
-1/-1 counter on target creature that entered the
battlefield under opponents' control this turn.
{2}{g} This creature gets +1/+1 and Fights target
creature that entered the battlefield under
opponents' control this turn. {2}{r} Each other
creature under your control gains Mentor and
+1/+0 until end of turn. {2}{w} Gain 1 life for each
Cat or Human