[The terlen has a weird backstory. The original creature was the terl, a flying fish monster from Gamma World. It lost its mutant powers and gained a very slow land speed when it became the terlen, a Planescape monster that was basically a winged barracuda. It became more shark-like when it was converted into the 3e Fiend Folio, but a copy-paste error made all of its speeds the same–60 feet. So imagine a winged shark zooming around on land without any legs. Warmed the cockles of my heart, it did.
In college, I ran an occasional pick-up game for friends in my home town, and the terlen ended up in one adventure. We rationalized its land speed as it having legs, and sketches were made (although they never ended up online). The above pic is pretty close, although our head-canoned terlen was a quadruped.]
Terlen This creature looks like a shark with large,
membranous wings and a pair of powerful legs. It moves with surprising speed.
Terlens are
all-terrain ambush predators, fish-like monsters capable of preying on
creatures of the land, sea and air. They are found throughout the evil aligned
planes, and are believed to be the result of some fiendish experiment. By the
standards of their home planes, they are fairly weak, and cruise the waterways
in search of fiendish vermin and animals, petitioners and minor fiends to kill
and consume. Their skin can change color and pattern, granting them excellent
camouflage—they use this ability as much to avoid detection from greater
hazards as to ambush their prey.
A terlen rarely
stays still in combat, preferring to make hit and run attacks. They are adept
at attacking from odd angles when flying or swimming, catching foes off guard.
A terlen will usually save its burst of speed to flee from an encounter it
cannot win. They travel in social groups, but these schools are not
particularly cooperative. A hungry terlen will happily turn on and consume its
fellows if given a chance. Terlens are egg-layers, and they leave their eggs buried
in moist soil on riverbanks or in marshes. Although they are most comfortable
in the water, they can survive on dry land indefinitely.
The true origin of terlens is unknown, but their ravenous appetite can swiftly cause disruptions to local ecosystems, especially when they school. The faiths of all the First Gods dislike them, and will hunt them when possible.
Shores of Swords 