Gigalith is a massive boulder-like Pokémon that resembles a golem and a stalagmite. Its entire body is made of deep bluish gray rock. It has bright red crystals protruding from all over its body. On its face, two sharp crystals protrude from the sides of its mouth like tusks. Its four limbs are bulky and powerfully-built. It has fierce-looking deep-set yellow and red eyes.
Gigalith was first seen along with Reuniclus and Gothitelle on Oha Suta on June 28, 2010. Later it was seen in battle against Blitzle, Darmanitan and Drilbur. On the Oha Suta episode of July 22, 2010, it was then revealed to be called Gigaiasu. It was later shown in detail at the Pokémon BW: Search for a Legend tour on August 7, 2010. It was also appeared on the September issue of Coro Coro on August 9, 2010. The Romanization of the name Gigaiasu was later revealed to be Gigalith.
Gigalith is likely based on a boulder-like golem, mixed with traits of a stalagmite and a geode.
Gigalith's name may have been derived from ギガス Gigas, a term used to describe a race of chthonic (Earth-associated) giants, and the word "monolith", a large single upright block of stone.