I thought up what I thought would be a good gag for my "People with Issues" strip: one of the regular characters would be schmoozing at an academic publishing party (like such things exist), and upon encountering a bearded type would ask what he does. "I'm a professor of folklore and mythology," he replies. "Uh-huh," says my regular, "working on anything at the moment?" The academic proudly states "I'm writing a monograph on the vagina dentata," and my character replies "Cool, that's my favourite song from The Lion King."
Ba dum-bum.
BUT, before drawing it up, I thought I'd get a bit more background on the concept of the vagina dentata, so I looked at the Wikipedia entry. That was fairly brief, but there was also a link to an h2g2 entry so I followed that, and there found ...
that somebody there had already done the same gag (i.e. noting the similarity with the phrase "Hakuna Matata"). Damn, damn, and thrice damn.
Now, I *could* just draw the strip anyway, but it always feels to me like stealing, to use a gag that you know someone else has already used, even if you know you thought of it completely independently.
So, the moral of the story is:
If you think of a good idea for a gag, DON'T research it!!!