The hengrauggi, or hengra, was a predatory creature native to the ice planet Delta Vega. It had three sets of limbs, two used for running and another smaller hand-like set. It had hundreds of eyes. They also had a protrusion which served as a whip which they could use to grasp their prey. They were capable of traveling and attacking from underwater.
In 2258, a hengrauggi attacked a drakoulias as it was running after James T. Kirk, who was marooned on Delta Vega. After disposing of the drakoulias, the hengrauggi commenced with chasing Kirk itself.
The hengrauggi ultimately chased Kirk into a cave, where it wrapped its whip-like protrusion around Kirk's leg and proceeded to pull Kirk towards its mouth. Before it could, however, it was repelled by Spock wielding a lit torch. (Star Trek)
Other than being physically powerfully and frequently roaring, the hengrauggi was additionally described in the script of Star Trek thus; "It's nearly 30 feet tall, red, hundreds of eyes" as well as having "sharp spear limbs" and a "disgusting, wet, teethy mouth." The script also compared it to the drakoulias, exclaiming, "This thing is so much worse!" 
The hengrauggi was designed by Neville Page. Page also designed the monster for the J.J. Abrams-produced film Cloverfield, which shares some similarities with the hengrauggi. Its head was inspired by a prolapsed rectum.  According to the Blu-ray, it is a sea creature.
This animal was nicknamed by the crew as "Big Red", though it was also often referred to as a "lobster monster". In a tie-in flash game produced by Esurance for the film, it was referred to as a "snow slug". Its short name comes from the film's audio commentary. In the film's script, it was referred to as a "Hen-Gra", in an ultimately unused line of dialogue in which Spock would have also described it as "notoriously afraid of heat." 
- Hengrauggi at Memory Beta, the wiki for licensed Star Trek works
- Star Trek's Beast Master Reveals How to Create a Monster at Wired.com