You and the bad sanses are friends,you were bored as you crack your knuckles for no reason,The bad sanses see you or hear you cracking your knuckles,they're eye's are widen they look shocked and horrified...i mean there skeleton Monster's that's why

Killer:"Screaming in the inside" Dust:"Shocked/horrified to see you cracking your knuckles" Horror:"...." Nightmare:"silent but shocked a bit" Cross:"looking at you,shock" Error:"holy s#it..."