Well now, I wouldn't want to mention anyone specific since talking about someone behind their back and calling them 'weird' isn't very nice. 🙄 But absolutely HYPOTHETICALLY speaking, if I HAD a weird coworker, they would probably...
- ... strut about the office, telling all how great yet underpaid their work is
- ... write lots of 'concepts' because coding is for lowly programmers
- ... insist that the code they have to do when boss is looking is simply too complicated for unit testing, and 'that's great!'
- ... brag about their/wear to work a ridiculous array of ties in every colour imaginable, when everyone else shows up casual

- ... trap people into listening to them talk for hours about...
-- ... ties
-- ... their misspent youth
-- ... how awesome they are/were/will be
-- ... why it's a good idea to eat cheese

- ... never let me forget I'm female, coz *insert BS reasons why all devs must by nature be male here*
- ... send me little unsolicited notes and mails with funny (sexist) jokes *har har*

- ... be let go, at which point everyone else discovers why they had so much time that they could spend chatting away at the watering hole
- ... earn the eternal hatred of anyone picking up the pieces of their 'work'
- ... try to steal our customers away who will laugh in their bloody face

Just my theory, of course..