Maze of Ith

Land

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

2020-08-07:
Maze of Ith really is a land with no mana ability. It doesn't tap for colorless mana.
2020-08-07:
Maze of Ith can target an untapped attacking creature. It will still prevent the combat damage it would deal and be dealt.
2020-08-07:
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.
2020-08-07:
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.