When leashed to a humanoid mobs can play tug of war

This is really cool. There should be a mark if one mob pulls the mark over the person who leashed it, that mob would win and the other would lose. This can happen with a wandering trader's llamas. But only two mobs leashed should play and/or the aggressive mobs such as iron golems. This can't work with a fence post or anything that you can tie mobs to. Just humanoids.