Rensa, the Timeshifter

At the beginning of combat on each player's
turn, choose one—
•Untap target permanent. If it's a creature, it
gains first strike and haste until end of turn.
•Tap target permanent.
{t}: Remove target attacking creature from
combat. You may untap it. If you don't, it deals
damage equal to half its power, rounded down,
to defending player or planeswalker.