Armaldo is a bipedal, amphibious Pokémon, somewhat resembling a mantis shrimp. It is covered with thick, grayish-blue plates. There are accents of yellow, black, white, and red throughout its body. Its oblong eyes protrude from the sides of its head. A black pattern with two red, teardrop-shaped spots covered the center of its head and a yellow lower jaw. Three pairs of wing-like appendages extend from the sides of its long, thick neck. A plate of armor on its back has four short spikes and two triangular, yellow-rimmed wings extending from underneath. Its scaled chest and belly are rimmed with yellow lines as well, and there are two large yellow plates in the center of its chest. Its segmented arms extend from holes in these plates, each with a large, black claw. The legs are also segmented, with black knees. A pair of black fins tips its long tail.
In ancient times, Armaldo lived on land by the water's-edge, and dived into the ocean to hunt for prey. The large wings on its back were used for swimming, while its thick shell protected it from enemy attacks. Its strong claws can break stones and punch through a steel slab. Furthermore, they can be freely extended or retracted. It is considered to be the ancestor of some Bug-type Pokémon.
Armaldo made its main series debut in Lights, Camerupt, Action!, where it was seen in a movie that was shown by Elijah. Its role in the movie was defending a castle where a Kirlia princess was held captive.
An Armaldo appeared in Where's Armaldo?, where, after evolving from Anorith, it was captured by Team Rocket but ended up going on a rampage.
Pokémon Mystery Dungeon: Explorers of Sky: An Armaldo serves a mentor to the future Guildmaster Wigglytuff while he was still an Igglybuff. Initially reluctant due to Igglybuff's devil-may-care attitude, he takes him on as an apprentice after sensing a powerful intuition from the baby Pokémon and eventually grows close to the young child. He tends to lampshade many RPG staples, such as traps and bosses, but is just as easily fooled by them. Armaldo is in fact an outlaw and is caught after clearing the Fortune Ravine. Igglybuff protests wildly and is about to unleash a powerful Hyper Voice (the first show of his infamous temper), until Armaldo calms him down and explains the situation; he gives the still-protesting Igglybuff a Defend Globe (the first treasure the pair found on their first adventure) as a gift to remember him by, and Armaldo willingly gives himself up to the authorities. This story serves as the backdrop for the second Special Episode, Igglybuff the Prodigy.
He later reappears in Pokémon Super Mystery Dungeon, where another Igglybuff requests the player to deliver a Tiny Reviver Seed to Armaldo. Upon delivery, Armaldo muses about another Igglybuff he knew that had become a respected guildmaster.
Spoilers end here.
This Pokémon was unavailable prior to Generation III.
Armaldo and its pre-evolution are the only Pokémon with the Ability Swift Swim that are also weak to Water.
Due to an error, Armaldo has the move Slash in its moveset twice in Pokémon Sun and Moon; once at Level 25 and again at Level 34. This issue was likely overlooked as Armaldo was unavailable in those games. It was later fixed in Ultra Sun and Ultra Moon, with Bug Bite replacing Slash at Level 25.
Armaldo appears to be based upon the Anomalocaris, although it shares some physical traits with dinosaurs.
Armaldo may be a corruption of armor, or a combination of "armor" and "ald", an old Saxon word meaning "old".