Keldon Overseer

Kicker {3}{R} (You may pay an additional {3}{R} as you cast this spell.)
Haste
When Keldon Overseer enters, if it was kicked, gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.

The List

Dominaria

Kicker {3}{R} (You may pay an additional {3}{R} as you cast this spell.)
Haste
When Keldon Overseer enters the battlefield, if it was kicked, gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.

You can target and gain control of an untapped creature with Keldon Overseer’s ability. You can also untap a creature you already control and give it haste.