One of my favorites was playing a senile mage called 'Frump'.
He was actually a deity with severe dementia, but had a skill bind that required him to not knowingly hurt anything alive by direct or indirect means.
The fun part of this character? Whatever he would imagine (in his dementia-spurred brain) would become a reality.
It would not be uncommon to have him walk over a pit and just stand in mid air.
The general commentary would be something like:
Party Member: Frump, um... careful of that pit?
Frump: head scratches what pit?
Party member: The pit you're currently hovering over?
Frump: *stamps foot down, you hear a dull 'thump' I'm standing on the ground.
Party member: No, it's a pit.
Frump: just blinks like player is stupid nooo, I would know if I was hovering
Second party member comes over to Frump, walks up to him and immediately falls into the pit shouting in agony
Frump: Hey! I"m standing over a pit! (immediately falls into the pit)
hear a whump, and someone dusting himself off
Frump: At least the pit didn't have any traps like spikes in it.
Party Member: Actually the pit... [muffled]
is immediately silenced by the other party members
Yes. The pit did have spikes.
The beauty of this? The party members started to realize that Frump on the odd occasion could twist reality to make what he believed to be real, well, real.
So someone picks up a rock, walks up to Frump and says 'Hey, isn't this the most BEAUTIFUL diamond you have ever seen?'
And well, sometimes Frump will agree, it's a beautiful diamond. Other times he's wondering why you're holding the most deadly spider in the world in your palm.
There's just no telling with good ol' Frump...