Official artwork for a Beetle.
Beetles (Beetals in early versions of Metroid Prime) are an insect species native to Tallon IV. Predatory tunnel diggers, Beetles live in soft earth and often spring up on unsurprising prey. They are also very territorial and extremely aggressive, which is why they attack Samus, who is a much larger creature than them, and most likely Phazon poisoning contributed to this excess aggression as well. They are equipped with powerful mandibles with which they use to kill and ingest food. The mouth of the Beetle is also for travel as they use it to burrow through solid rock at high speeds. Samus encounters them in Metroid Prime, where they can be found in the Tallon Overworld and in the Chozo Ruins. Beetles sometimes make an odd pig-like noise.
Ice Beetle
Ice Beetles, a related species, can be found in Phendrana as well. They have reinforced ice carapaces, which provides extra protection and augmented burrowing strength and abilities, and they despise any type of heat. Usage of any beam, excluding the Ice Beam, causes it to flee back into the ground, although the Plasma Beam makes short work of them (they even have a special death animation used for it). Ice Beetles burrow quickly and are even faster in their attacks making preparation a dream against them. They are short-lived enemies, appearing in only one or two areas in the game and in small numbers.
Plated Beetle
There is also a larger species related to the Beetle called the Plated Beetle that is also found in the Chozo Ruins. This Plated Beetle species is not a fully grown "Alpha Beetle" like some might think, but rather a large cousin of the Beetle species. These have many distinct differences, such as a plated exterior, and a vulnerable abdomen at the rear.
Scans
Beetle
"A burrowing insect with a resilient carapace that's extremely aggressive. Beetle's massive mouth enables it to tunnel through solid rock at high speeds. Above ground, Beetles can cover short distances rapidly. They attack anything that moves near their lair."
Ice Beetle
"Ice Beetles are burrowing insects with an ice-reinforced carapace, and they have an aversion to heat of any kind. This member of the Beetle family has adapted to life in the subzero temperatures in the Phendrana Drifts, growing a thick ice shell over its entire body. The ice is extremely resilient, providing the Ice Beetle with extra protection and augmented digging abilities."
Early version of Metroid Prime with "Beetal" name.
Plated Beetle
"The Plated Beetle is a burrowing insect with an impermeable carapace. This creature is only vulnerable in the rear abdomen. Unlike its lesser cousin, the Plated Beetle can repel frontal attacks. It prefers to impale its prey upon its six sharp horns. Only surfacing when it detects vibrations above, it then maneuvers itself so as always to face its rival, keeping its exposed abdomen protected."
Metroid Prime Pinball
"A burrowing creature that attacks by charging its prey."
- Metroid Prime Pinball features a minigame called Beetle Blast.