Tsetse fly

A tsetse fly is a monster in SLASH'EM which, true to its real-world counterpart, can put you to sleep with its attacks. It appears only Gehennom, by which time any SLASH'EM character is likely to have sleep resistance, making it essentially a non-threat. Even without sleep resistance, it is not that much more dangerous that a homunculus, not being able to put you to sleep for significantly longer.