A quick Google tells me that you're looking at a Texas Chainsaw Massacre reference. I can't confirm it, but Googling tells me that both the Despicable Me movies and the Minion film have Haloween, Chainsaw, 28 Days and numerous other horror movies referenced in such a way that only the adults would get the joke.
I found a particularly pertinant quote about why such jokes end up in films, tho this was about Pixar, and will probably answer your question, as to why the chainsaw sequence was even there.:-
"These inside jokes for the adults in the theater are something Pixar has mastered in their films at this point, and throughout the oeuvre of that studio are jokes containing a layered humor which manage to appeal to kids and adults simultaneously. They may be laughing for different reasons, but everyone can laugh together – the reason Pixar is considered the masters of the “family” film."