The behir is a common reptilian monster in many fantasy role-playing games.
The behir appears as a 40 foot long long crocodile-headed snake, with 6 legs on each side. These legs allow the behir to outrun almost any man, and climb almost as fast as it can walk. The behir can also move in the same manner as a snake (if it needs to get through a tight spot), by folding its legs up close to its body and slithering on its belly. The body of the behir is covering in overlapping band-like scales that are some of the most effective natural armor in existance. Most behirs will have a pair of horns on their head, but these are for grooming, and not for attacking.
The behir will usually live alone (often in a cave high up the face of a cliff). They wander widely though, usually patrolling an area of several hundred square miles. The behir are very jealous of their status as the largest predator in the area, and they will not allow another behir or dragon to live in their hunting range. They will drive these creatures out, or leave themselves. The behir will only meet up with another of its kind to mate. The male and female will stay together for the 8 months that it takes for the eggs to hatch. After which, both of the adults will leave the area (leaving the newly hatched behirs to fend for themselves). The freshly hatched behir will only have 6 or 8 legs, and the others will grow in as the creature matures. These newborn behirs are only a few feet long, but they are strong enough to fend for themselves against most natural creatures.
A behir is quite a dangerous foe (on the same level as a dragon). They attack by biting, and then coiling their body around the victim like a snake. An over-anxious behir will often swallow his target whole (it is possible to cut your way out of a behir's stomach, but you only have a few minutes to do it before you will suffocate). The behir also possesses an electrical breath weapon (much like that of a green dragon), that it can use every ten minutes or so. This bolt of lightning will kill most normal men instantly, but a powerful warrior can survive it.
The body of a dead behir to an alchemist is like a dead buffalo to an american indian. Almost every part of it has magical, or chemical properties. Even their scales can be used to fashion several sets of high quality ultralight scale mail armor.