Shelmet is a snail-like pink and green shelled Pokémon. It has a long pink proboscis sticking out that looks very much like lips, and it has large eyes with small black pupils. Its grayish shell serves as it's armor, which resembles a knight's helmet.
Shelmet and Karrablast only evolve when both traders trade that Pokémon. They are the first Pokémon to do this.
Despite having the metal "shell", it is not Steel-type.
It is shown, when traded with a Karrablast, it takes Shelmet's helmet, deshelling it and causing it to evolve into Accelgor, the Shell-Out Pokémon. Karrablast then evolves into Escavalier and wears Shelmet's armor.
Shelmet is based on a nautilus. Its shell also resembles a knight's helmet, with the visor open.
Shelmet's name appears to be a portmanteau of "shell" and "helmet".