"Hello Kitty on acid" is the popular description of this one. Looks accurate to me.
It starts out deceptively small. The title sequence is simply following a trail of paw prints. This is endearing and made me smile. However the anime doesn't star real cats, but instead anthropomorphic ones who own and live in a (Japanese) house. Our family has two children and their parents. They're cute. You'd think it was a children's anime, except better animated. It's drawn in a slightly primitive style and the characters talk in strange noises that are never the same twice, e.g. like squeaky toys. If anyone ever says anything we need to understand, it'll be written (in Japanese) in a speech bubble coming out of their mouth.
It begins domestically enough, with one of the children (Nyatta) drowning in the bath and, while clinically dead, seeing his sister (Nyako) being taken away by a Buddhist bodhisattva called Ksitigarbha. (In Japan he's called Jizou and his responsibilities include children, dead children and aborted foetuses.) Anyway, the boy and Ksitigarbha play tug-of-war with the sister and rip her soul in half.
This is the gentle beginning that lulls the audience into a false sense of security, by the way. It's a bit weird, but that's okay. The presentation is fluffy and kiddie-friendly, with the death and afterlife stuff being presented on a par with Laurel and Hardy dying and coming back exactly the same, but with harps and haloes.
After that, it gets extreme.
The first bit to make you furrow your brow is a super-violent and gory "saw a woman in half" trick at the circus. A magician does real magic, then a flood drowns the world and wipes out all of civilisation except for Nyatta, Nyako and a pig in a boat. (We're not even halfway through, by the way, and this is a minor plot development.) The anime starts taking a Svankmajer-like interest in food, with someone going to the toilet over the side of the boat and then refusing to eat the fish that swarm to eat their offerings. That would be disgusting. Instead they cut open their living friend and eat him instead, although not being a barbarian, of course they let him eat some of his own flesh too.
The atrocities and impossibilities in this anime are piled on each other in a manner that's not even pretending to make sense, like some kind of fever dream. (a) There's a Darwinian bit with a mother pterodactyl and a pregnant cat/woman falling off the edge of the world. There's jaw-dropping cruelty of a kind you could hardly imagine to (b) a pig and (c) a bird. (d) A fish gets turned into sushi, but swims away anyway as a fish skeleton. (e) There's a woman who'll sew your arm back on and has a collection of body parts and patchwork children. (f) There's a version of the Hansel and Gretel story, except even more gory and with a gimp outfit.
Then there's the out-and-out surrealism. An army of birds on stilts. God's clockwork universe. I don't have words to describe what the circus magician turns into.
What does it mean? There's a preoccupation with a cruel universe and a scary view of gods (including both Buddhism and what looks like the regular Judeo-Christian God). This God eats the earth. Literally. He puts it on a plate and everything. He's a bastard. The bit where time gets rolled back includes mankind's evolution from the animals, guillotines and people getting their brains blown out execution-style. Oh, and nukes. There's a minor running motif of people who are really robots, which might tie in with that clockwork universe. Water can destroy us all (as per Noah's flood), but later Nyatta and Nyako are in the desert and having to dig for it. Food and where it comes from is a huge, terrifying preoccupation.
...and then, at the end, we're back with Nyatta and Nyako's family. Everything's back to normal and they're going shopping for their mum, as she asked them to do a million years ago when the anime seemed almost sane. And then the world turns off.
It's based on a manga by Chiyomi Hashiguchi, pen name Nekojiru (a portmanteau of the Japanese words for "cat" and "soup"). She usually drew her main characters as cats, and her main themes were apparently childlike zaniness, cruelty and nostalgia. (I use the past tense because she committed suicide in 1998.) She also put a lot of her dream experiences into her work, often including psychedelic mushrooms and LSD. I have no difficulty in believing any of this. There had already been an anime before this based on her work, incidentally, called Nekojiru Theatre and comprising 27 two-minute episodes in 1999.
It won awards, including Best Short Film at the Fantasia Film Festival. Jan Svankmajer would go apeshit for it. Very freaky. Not even trying to make sense. It'll be way too fond of the gross-out for a lot of tastes, but then again it's drawn throughout to look like a children's show. The English title is more literally true than you'd expect, though. It's a reference to Nekojiru's name, but there's also, literally, cat soup. That's in the Hansel and Gretel bit.