Lurcher

Allomancy (Lurcher enters the battlefield with three
metal counters on it)
{t}, Remove two metal counters from this
Lurcher: Gain control of target artifact with
a converted mana cost of 2 or less until end
of turn.
Remove a metal counter from this Lurcher:
Until end of turn Lurcher gains flying as long as
it's attacking an opponent that controls
an artifact with a converted mana cost of 3
or more.