Nashi, Here and There

Whenever Nashi deals combat damage to a
player, you may pay {1}{u/r}. If you do, exchange
control of target artifact you control and target
artifact that player controls.
{1}{u/r}{u/r}, {t}: Exile Nashi, then return him to
the battlefield under your control. You may
return him to the battlefield tapped and attacking
target player or blocking target creature. If you
do, he gets -1/-1 until end of turn.