Cat meat?

There are absolutely cultures like that. I know people who cooked their pets after their pets died, because otherwise they would just be wasting good meat.

That is actually the case! Someone already mentioned kuru, which was a disease unique to the South Fore. My mom used to bring it up those who contracted kuru disease as an example of "savage" tribes, but actual anthropological studies show there was a lot more nuance than that, and it was very much done out of love. (Warning: I'm about to discuss that in some detail, so maybe don't read further if cannibalism/dead bodies is upsetting to you!)

I found this article really eye-opening in terms of cultural differences and why they chose to eat their relatives.

Here are some quotes from it:

A person has five souls (auma, ama, kwela, aona and yesegi) that depart from the body on the last breath but only the auma departs immediately to the land of the dead. The auma is similar to the western concept of a soul and consists of a person's good qualities. Once the auma has been forgiven by a close male affine for any transgressions committed during the deceased's life, it travels across the land saying farewell to the bagina [world]. When it reaches the amani, it explains to the clan guardian why it has died and the amani feeds the auma and directs it on the road to kwelanandamundi. Food and water left at the sepulture by the family provide sustenance for the auma on its journey. Eventually it reaches a red river at the entrance to the land of the dead and having crossed this it is welcomed by the ancestors. The auma then has to wait for the ama (bones) and kwela (flesh) to arrive before it can be reborn as an ancestor.

So the good parts of a person's personality are automatically preserved no matter what. But you can't actually become an ancestral spirit until your body is destroyed. By eating it themselves, the Fore thought that the deceased could pass their blessings and talents onto their favourite relatives while also being sped safely along on their journey to the afterlife.

The dying person would normally express their wishes as to how their body was to be disposed of; otherwise the family would decide. In the kuru-affected region, all methods of disposal of the body involved being eaten. If the body was buried it was eaten by worms; if it was placed on a platform it was eaten by maggots; the Fore believed it was much better that the body was eaten by people who loved the deceased than by worms and insects. By eating the dead, they were able to show their love and to express their grief.

So you had a choice of whether to be eaten or not, but most people wanted to be, because it was better to feed those you loved than insects (and better to eat those you love than let them decay).

After death, the family and relatives mourned over the body of the deceased for 2–3 days and then, if it was to be eaten, it was taken on a stretcher to a bamboo, sugar cane or casuarina grove. These sites were chosen as they provided shade to the mourners and the deceased's souls, making them happy.

This was just a cute example of how they took into account the deceased's spirit and the mourners during the proceedings. There were also a lot of rules, like not allowing any food to fall on the ground because it was disrespectful to the dead.