Did Mom Just Have Tea with Cthulhu? is now Villain Over for Dinner:
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman Hide / Show Replies
Much better name, since this trope doesn't necessarily (or usually) involve an Eldritch Abomination.
Sorcerer in training
In Elf Defense, Sandra doesn't actually walk in on Kelerison and her mother having tea; it's a planned lunch at a hotel restaurant where 'Mr. Keller' is going to 'get his colors done' by the elder Mrs. Horowitz. (Don't ask, and Sandra kept her maiden name.) Of course, the only reason the Elf King does that in the first place is to get the mother on his side in the 'divorce' action. Amanda being his former mistress; she eloped with a mortal before the King tired of her. Kel's son also went with her. It's a complicated but fun story.
Also includes the trope Poor Communication Kills, since Kelerison just kept chasing them all over rather then explaining he needed his son Cass present for peace treaty discussions with the native fairy races. There's also the talking cat, and 'fun' with fairy creatures. These are the creatures straight of Grimm, and they have to be outsmarted or bought off. Kelerison treats the conflict as one big joke until Sandra and Amanda sic the IRS on him. Serious Mood Whiplash in places, too.
It's a shame the book's out of print. Fun with Tropes and Tropes Are Not Bad all over. (Yes, I do have a copy. :) )
Coming back to where you started is not the same as never leaving. -Terry Pratchett
Also in Dragon Age II, if you accept the loan offered by Dougal near the end of Act 1, he will go to your home and have polite conversation with your mother before threatening you when you arrive.
Would Pig fit this trope? The climax involves the hero and his sidekick (who is the villain’s son) cooking a meal for the villain in order to get him to open up about the fate of the hero’s abducted pet.