Now sure if this qualifies as a bug (or is a tad too big). On holiday in Turkey 3 years ago, we got friendly with a couple from Northern Ireland.
(They were Omagh bomb survivors, although their daughter was badly injured - but that is another story.)
The wife got out of the shower one morning, opened up the fresh towels she had been given the night before, to find a 40mm scorpion wrapped inside. We heard the scream from 3 doors away...