Oh, no! You walked into the slavering fangs of a lurking grue.
Related:
grue n.
[from archaic English verb for `shudder' as
with fear] The grue was originated in the game Zork (Dave
Lebling took the name from Jack Vance's "Dying Earth"
fantasies) and used in several other Infocom games as a hint
that you should perhaps look for a lamp, torch or some type of
light source....