It's a morbid joke - referring to the green monster eating some humans.
BUT I think there is a typo (writing mistake) with the word "asked". It does not fit with the sentence. It should probably have been "had" or "exchanged".
Human = человеческий
Toast = тост
wolf = волк
Yum, yum = "sound that someone might make if they are eating something tasty, (that tastes good)
If you look closely at the picture, you can see that the green monster has some humans (people) In its tentacles....