Smells like death. Cats love it.
As the title says, this thing has earned the nickname “dead ferret” because it stinks to high heaven, but I haven’t yet met a cat that doesn’t go insane for it! I bought one each for my two cats, and when I bought a third as a gift, they dug it out of my bag, ripped the packaging open and started playing with it.
Even the neighbour’s cat Dave loves playing with them when he visits.