Mavrin, Intrepid Tamer

Vigilance
When Mavrin attacks, you may tap a creature
you control. Mavrin has all abilities of a creature
tapped this way and gets +X/+Y where X is that
creatures power and Y is that creatures toughness
until end of turn.
{w}{r}{g}: Gain control of target creature until end
of turn. This can only be activated once per turn.