Some spoilers for Undertale! Here be dragons!

The original post references a meme about Undertale's seven human souls, where 6 colorful human souls; representing different positive traits, are stolen by Flowey to give him unlimited power over the game. This turns him into a monstrous creature. (The 7th red soul is the one you play as.) 

Gargamel and Azrael were sold a costume of said monster (It's implied Sans the Skeleton scammed them into buying it) in the hopes that they'll be able to capture 7 Smurfs instead of 7 souls. Azrael thinks the idea is stupid!

If you haven't played Undertale, you should really give it a try, it's a fun and sincere game where you're rewarded for being kind to everyone. It only takes around 6 hours to fully play through from start to finish, and there are ways to make the game easier depending on how much trouble you're having with it. 10-year-old me was able to do it