Focus on a sick hunger of human flesh. The main male character undergoes torture and he suffer a lot both physically and mentally.
Both of these are quite similar with regard to the horror and cannibalism stuff. The difference between the two, however, is that Tokyo Ghoul has a plot.
Both shows are about the daily lives of human-like monsters that eat people.
Both anime show the daily adventures of sick cannibals with tones of random blood and gore.
Both are fairly gory shows that feature a person who suddenly becomes a human-eating monster and have to cope with their new lives. Pupa's plot is very incoherent though while Tokyo Ghoul makes a lot more sense, so if you liked Pupa you'll defintiely enjoy Tokyo Ghoul.
Both are psychological horror anime about monsters looking like humans (monsters who once were humans) eating humans. Both are gory and full of violence.
Both of these shows are a really really bad adaptation of a great manga. Both of them are edgy, have a weak MC and some kind of human mutation/deformation.
Some filthy casual is stripped from their ordinary life by a living being, turning them into flesh-feeding monsters. The protagonists both fear their new life ahead of them. Both filled with dread and disappointment
Dark themed, cannibalism, monsters. In some way, they're similar.
We have in here some similar stuff, like there was present a older woman when the main character (or at least one of the main) got his/her power awakened, and there's the part of someone need to eat flesh to survive.
These seem to both have somewhat the same "Humans are Tasty" theme. Another similarity would be that both contain more black screens than action. However pupa is in my opinion, even worse than mars of destruction for the fact that it was 12 episodes instead of just one, whereas Tokyo Ghoul was decent.
Monsters that eat human flesh are present.
-Both shows are Gorey
-Both shows are Psychological/Horror
-Both shows involve cannibalistic creatures.
-Both shows involve a human who was turned into a cannibalistic creature, within the first episode.
-Both shows feature a main character who has the ability to sprout a red tentacle-like weapon from out of their back.
-Both shows feature a little, cannibal girl with short, brown hair, brown eye, and a pink flower hair piece.
-Both shows contain a scene where the main character is strapped into a chair and tortured.