Dawn Swooping

At the beginning of your endstep, if you don't
control X Dawn counters, create a 1/1 Bird
creature token with Flying and "When this
creature deals damage to a player, gain control
of target artifact that player controls and
exile this creature. You get a Dawn counter."
When you control X Dawn counters, return
each artifact on the battlefield to their owner's
control. You gain X life.