Antler lock-ups are where two Whitetail Bucks, or even Bull Elk, battle for supremacy and end up locking their antlers together. We’re talking antlers and not horns. See here for discussion on the difference between horns and antlers.
Here other posts of similar events:
This pair got locked and the winner drug the other around until he got tangled up in a barbed wired fence: Deer Locked Horn-to-Horn
The winner here drug the other around while other critters — assumed Coyotes — ate the loser: Another Deer Locked Horn-to-Horn
Here’s a really cool post about Elk getting antler locked. Amazing Two Bull Elk Locked Horn-to-Horn
My favorite is a 3-way buck lock-up.
See all my posts on Antler Lock-ups here.