Twiddle

Instant    (CMC:1)

Tap or untap target artifact, creature, or land.

111 8ED • ENMatt Cavotta

™ & © 1993—2003 Wizards of the Coast

Legal in: Modern,Legacy,Vintage,Freeform,Prismatic,Tribal Wars Legacy,Singleton 100,Commander

Oracle Text (click to copy):

10/4/2004
This is not a toggle effect. If you use Twiddle to tap a card and before it takes effect your opponent taps it, Twiddle will not automatically untap the card.
10/4/2004
The decision whether or not to tap or untap is made on resolution. This is not a modal spell.