Had a cat once that loved baked beans and marmite.
Nastiest thing, though, was a friend's dog who had a passion for used condoms. It's turds would come out half-wrapped in shredded latex (I assume the contents had been digested). Friend's girlfriend used to mutter about the bloody dog sniffing around the lover's lane at the bottom of the garden, but friend once confided in his cups that the dog would simply snaffle the used johnnies from under the bed after the soggy deed. For some reason he couldn't be arsed to dispose of them in a dog-proof way.