Mario loves to eat. My nickname for him is "Chunky Monkey." He'll eat most anything if it is presented to him as food. He has slowed down a little and is a little more discriminating in his older age, but when he was younger he'd eat first, think later.
My parents were over visiting once and my dad was eating an orange (my dad eats usually eats an apple a day and Mario loves him and the never ending apple peel source). My dad asked if the rabbits could eat the orange peel. I have no clue if this is a bad thing to do, but I told him he could try.
Mario came running over as my dad approached. The fuzzball can sense a treat coming. He grabbed the orange peel out of my dad's hand and commenced gobble-down action. Chloe refused her piece. Mario had been chewing the peel for about 5 seconds when all of a sudden he stopped.
His nose began to wrinkle and twitch. You could tell he didn't quite understand what was happening. He then began doing something I've never seen a rabbit do and have never seen Mario do since. He started hitting himself in the face with his paw. None of the normal rabbit-cleaning-it's-face action. He was smacking himself. It was hilarious.
He did end up eating a little more of the peel afterwards.
I don't have a picture from the actual incident but here is one of Mario and Chloe waiting for their share of the apple peel bounty after my dad had his nightly snack: