I once left an apple in a pint glass under my bed
over the winter holidays in halls of residence. It wasn't deliberate; it was just in the farthest corner, hidden from all earthly detection.

Except nasal, of course. On my return, I was greeted with (when I finally found it) about half a pint of a liquid that was almost, but not quite, entirely unlike cider. Even in an environment of first year med students, vets and rugby players, challenges to drink the remains were met with universal rejection.

Eventually I flung it down the toilet, which - no kidding - spat it back out when I pulled the handle. Someone claimed that this was because they'd flushed out some of the plumbing over the holidays (a regular requirement around first year students, who on average have no idea what is acceptable to put where) and that there'd been air in the system, and that it was the first time the toilet had been flushed since so it was bound to be dodgy.
I knew the truth, of course; the liquid was so vile that even the porcelain maw couldn't bring itself to swallow.
(Falstaff's Spiritual Successor, Wed 8 Feb 2012, 19:21, Reply)