Abyss Watcher

First strike, Trample, Melee
At the beginning of your upkeep, create a tapped
token copy of Abyss Watcher, except it's not
legendary. If you would create a second token
copy, target opponent creates a tapped token
copy of Abyss Watcher.
When a nontoken Abyss Watcher leaves the
battlefield, exile all Abyss Watcher tokens.