origin: (1929) German; witzeln= to affect + Sucht= mania.
Do you know someone who makes jokes at the most inappropriate times?
A person pulling puns until you want to punt them?
It's possible they actually suffer from a mental disorder! Witzelsucht is a frontal lobe disorder (caused by tumor or lesion) that exhibits: a bleak sense of humor and/or obsessively telling bad puns, pointless rambling stories, and being friendly or enthusiastic nearly to the point of hysteria. In rarer cases, they also exhibit hyper-sexuality and their words can take on inappropriate sexual references.
However, those who suffer from the condition are unlikely to laugh at other people's jokes.
So...sort of like Beetlejuice, The Joker, or Deadpool.
In short, Witzelsucht can be summed up as "joke addiction".