Auditory hallucinations are most common. The sounds of flies buzzing around your head non-stop, creatures climbing up the walls/ceilings

Also, fun fact, there is a couple mnemonica for anticholinergic poisoning and they go:

red as a beet, dry as a bone, blind as a bat, mad as a hatter, hot as a hare, and full as a flask

But in pharmacy school we mostly said:

“No See, No Pee, No Spit, No Shit”