Dessgeega

The Dessgeega is a crab-walking (and jumping) creature that is usually found in extremely hot places (i.e. volcanoes, deep underground). Samus first encountered this enemy in Ridley's Hideout on Planet Zebes, in Metroid. This xenotropic life-form's deadliest attack is to simply jump on its target (some demonstrate the unexplained ability to jump on ceilings). This can cause massive damage, not only because of the weight of the creature, but also the sharp spikes running down the sides of its legs. This creature's natural armor is resilient as well, making it a dangerous enemy. Dessgeegas are usually known to be stronger than their Brinstar relatives, the Sidehoppers.

In Super Metroid, there were massive Dessgeegas located in the lower depths of Norfair. These are most likely adult versions, and are around twice the size of Small Dessgeegas found in upper Norfair.

In Metroid Fusion, they appear in Sector 2, or "TRO", the tropical sector. The mimicked/X-infected Dessgeegas have been given a new coloration, thrusters and the ability to shoot out darts from their legs (which seem to be coated with additional thorns), but surprisingly, the Dessgeega-X are actually less armored than their normal forms (as they take fewer shots to die).

In the remake, Metroid: Zero Mission, another species related to the Dessgeega was introduced, currently known as the Baristute. These creatures were stronger than both the Dessgeegas and Sidehoppers in the game.

Metroid: Other M features the Dessgeegas for the first time in 3D. In this game, all previously mentioned hopping creatures are capable of causing a small shock wave as they land after a large jump. The Dessgeegas and Baristutes have the exclusive ability to spit out a web-like substance that immobilizes Samus for a few seconds, rendering her vulnerable to any other attack the former two might perform.

Dessgeegas are often mistaken for Sidehoppers. 'Big Time' Brannigan also resembles one. It is unknown if either have any relation to the similarly named Geegas.

Metroid manual
"They jump toward Samus to attack him and are the second strongest creature in the hideout after the Mini-Boss. It takes several blasts of the normal beam or one missile blast to destroy them."

1986 manga
"Jumps repeatedly, attacking Samus. The miniboss comes after them."

Official Nintendo Player's Guide
"It attacks bounding like a strong spring. This is the second strongest enemy in Norfair."

Super Metroid Nintendo Player's Guide
"They are quite strong. Stand back and blast them."

Trivia

 * It is interesting to note that while Dessgeegas are native to volcanic areas, they are found in Sector 2, the tropical habitat on the BSL station. Additionally, Sidehoppers, who live in tropical areas, are found instead in the volcanic Sector 3 aboard the BSL station. The X Parasite's ability to manipulate DNA could be the cause for this abnormality. Also, their new long range weapons could be a result of the parasite combining another infected creature's DNA with the Dessgeega (the plant known as Cacatac possesses the same attack, and may explain the added spikes on Dessgeega-X as well).
 * In Metroid: Other M, Samus also encounters two Dessgeegas at her first visit to the Cryosphere but after being destroyed, they won't reappear, being replaced by Baristutes instead.
 * Although famous for their jumping, Other: M shows that Dessgeegas are also capable of burrowing, as the first one she encounters jump out of the ground to attack her.
 * In Metroid: Zero Mission, Samus actually encounters a Dessgeega shortly after obtaining the Long Beam. This is the only Dessgeega seen in Brinstar, and is a sort of mini-boss.