>>47588670If I don't get to choose the method of death, then probably Gengar. Its Pokédex entries say that it reduces the air temperature and then draws the life force out of its victims, which would probably be like getting really cold and then falling asleep. It doesn't sound comfortable, but it doesn't sound particularly painful either.
If I get to choose the method of death, then I'd want an Incineroar to suffocate me with its ass