Tracer, Speeding Justice

Commander Dash {1}{w/u}{w/u} (You may cast this spell
for its dash cost. If you do, it gains haste and it
is returned from the battlefield to the command zone
at the beginning of the next end step)
Whenever Tracer, Speeding Justice enters or
leaves the battlefield, you may return target
artifact or creature to its owner's hand.
"Well, cheerio, here we go again!"