Notes:

Spaghetti sauce

I haven't played Undertale so I don't know if this is a spoiler or not. I think it is but I'm not sure. I'll take off the spoiler if someone can confirm. I think NSFW should be here as well since there's off-screen 100% lewd going on, but again I'll remove it if it's unnecessary.
EDIT: I removed the spoiler tag (based upon comment feedback) and added the artist to the tags since I forgot to do that the first time around.