Coworker constantly takes credit for colleague's work, colleague starts leaving easter eggs in their notes: 'I embedded a completely fake bullet point right in the middle'

When someone else takes credit for your work, what can you do about that? This employee figured it out. 

It can be frustrating when somebody else swoops in and takes credit for something that you did. Maybe this happened to you on a small level in a conversation in a group. Maybe you had a funny quip or joke, and you said it, but you said it kind of quietly. Maybe only a couple of people heard. And then somebody else swooped in and says the same thing just in a loud voice, and it crushes. This happens all the time, and is a classic way that we experience getting our work taken credit for by somebody else. It can be an incredibly frustrating experience, but an incredibly common one. It's even more frustrating, though, when this happens at work. You work hard to do the things that you do, and you don't want to see somebody else take credit for everything that you do. It could be a hindrance in your professional career.