history: A colleague at my job took credit for months of my work and claimed I was of no help to them. It all worked out as it should have in the end, but that's never an easy situation.
current: I recently was in a situation at work where I had a colleague take credit for months of my work, and go out of their way to tell my boss and others in a committee that I actually held the team back.
next: Ugh I hate crap like that.  Why can't credit be shared?  Does it always have to be so cutthroat?