This next conversion is one of those creatures with "fill in the blanks" options.
A tymphanix, native to the elemental plane of earth, is kept here by the ettins [...] as a watchdog and an early-warning device.
"[...]Between you and the exit is a short creature that looks like a cross between a stone scorpion and a kettle drum. The gray creature clicks its pincers at you and drums its club-like tail against its top carapice, beating a warning."
Tymphanix: 1; AL N; IN Low; SZ L; MV 6"; AC 5; STs 13, STw 12; HD 7; hp 35; THAC0 13; #AT 2 pincers/1 club; Dmg 1d8/1d8/2d6; XPV 630.
Special Defenses: Immune to normal weapons; takes half damage (save for quarter) from fire, cold, and lightning attacks.
Notes: Drums on its hollow carapace to warn off strangers from its lair.
Originally appeared in Polyhedron #31 (1986).