Tracer, Slipstream Pilot

Flash, haste, vigilance, double strike
{t}: Tracer, Slipstream Pilot phases out.
Whenever Tracer, Slipstream Pilot phases out,
put a pulse counter on Tracer, Slipstream Pilot.
{r}{r}: Remove all pulse counters from Tracer, Slipstream Pilot. Deal X damage to target
creature and that creature's controller, where
X is the amount of pulse counters removed
this turn.