Larvesta "flying" using the fire that spits out from its horns
Larvesta is a fuzzy, moth larva-like Pokémon. It has blue eyes in a shadowed face. Its white mane of fuzz encompasses its head and the upper half of its body, while its lower half is brown. It has three pairs of small black legs. There are five red, slightly whorled horns on the sides of its head, which it can use to spit fire as a defensive tactic to deter predators. It has been seen using fire it spits from these horns to fly. Larvesta's flames can reach up to 5,500 degrees Fahrenheit in temperature. It lives at the feet of volcanoes, though it was once believed that Larvesta nested on the sun.
Larvesta and its evolution are also the only Pokémon with a double weakness to the Rock type that are not Flying types.
This makes them the Pokémon vulnerable to the most damage from entry hazards, able to be affected by both Stealth Rock (from which they take maximum damage) and Spikes.
Larvesta and its evolution are the only Pokémon that are neither Legendary nor Mythical that learn a move upon reaching level 100.
Larvesta may be based on a moth — likely an Atlas moth larva — and the Tower of the Sun, a famed Japanese monument. The way its red growths are shaped and positioned on its circular body may be a reference to the sun or to the Daimonji. It may also be based on a torch or cigarette.
Larvesta may be a combination of larva and Vesta (Roman goddess of the hearth and home, symbolised and represented by an eternally-burning fire located in her temple). It may also involve lava.
Merlarva may be a combination of めらめら meramera (onomatopoeia for flaring) and larva.