Source: Bestiary, pg(s). 226
Appearance & Ecology
Like the others of its kind, a tarn linnorm has a long, snake like body and two clawed feet. However, it is distinguished by having two heads. A tarn linnorm can grow to over 120 feet long, and can weigh over twelve tons. Fortunately for other races, it spends much of its time sleeping at the bottom of mountain lakes.1
The tarn linnorm can exhale a cloud of deadly acid. Even if the acid fails to kill its target, the subsequent fumes are poisonous. Both of the creature's heads can use its breath weapon at the same time, enabling it to encompass a large area. The creature's bite is also acidic, as well as being poisonous, and it can also attack with its sharp claws and powerful tail.
Anyone who somehow manages to kill a tarn linnorm risks being afflicted by a curse which prevents all natural and magical healing of wounds.1