The Invisible Man

My brother went somewhere to eat. He picked up the ketchup bottle to use it, made sure that the lid was on securely, then shook it up. The lid flew off anyway, and he dumped ketchup all over the side of his head, on his back, and everything around him.

People nearby were rather confused at the ketchup everywhere, wondering where it had come from. Nobody noticed the unfortunate man covered in red glop.

As a waitress walked by, my brother asked if he could get a towel. She looked at him with shock, finally realizing where the ketchup had come from. She hurriedly got a towel for him, and he cleaned himself and the wall behind him. The waitress then brought him a different bottle of ketchup, and told him it was pre-shaken. "Thanks." my brother said wryly.

It's amazing; everyone sees the mess, but no one sees him. Once again, my brother is the invisible man.
In fact, when he goes shopping with people, they occasionally lose him. He'll stop or go down another aisle to look at something. When they notice he's gone and look for him, they can't find him, even if they walk past the aisle he's in. Over six feet tall, and he's invisible.