Maze of Ith

Oracle Text

T: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Card Rulings

6/8/2016 Maze of Ith can target an untapped attacking creature. It will still prevent damage in that case.
6/8/2016 The creature isn’t removed from combat; it just has its damage prevented. It’s still an attacking creature until the combat phase is complete.
6/8/2016 You can activate Maze of Ith’s ability targeting an attacking creature you control during the combat damage step or the end of combat step. It’ll be untapped and the damage it had already dealt won’t be undone.