Can I untap an opponent's attacking creature with Kiora's Follower's ability, and avoid the combat damage that I would be dealt by that creature in the combat phase?
1 Answer
No.
506.4b Tapping or untapping a creature that’s already been declared as an attacker or blocker doesn’t remove it from combat and doesn’t prevent its combat damage.
You need something that specifically removes it from combat, like Maze of Ith. Actually causing it to leave the battlefield will also stop its attack, even if it comes back right away.