Years after the game's launch, Death Stranding players have discovered that if you refuse to fight Higgs in his boss fight, he will eventually bite your ear off.
To lose your ear, which is a permanent feature for Sam in the rest of the game if it happens, you'll need to just block Higgs' attacks, without fighting back or counterattacking when you're in his grasp. Considering you are usually meant to fight a boss, it's little wonder why few have discovered this neat detail.
It just goes to show the attention to detail in Death Stranding that something like this has been left as a secret for years. With Death Stranding 2 in development, hopefully similar hidden details can be found in that game too.