Amorphous

From Pokemon - Wiki on Neoseeker

The Amorphous (or Indeterminate) Egg Group contains Pokemon which are strange in shape, or lacking of any shape at all.

List of Pokemon in this group

Banette
Castform
Chimecho
Drifblim
Drifloon
Dusclops
Dusknoir
Duskull
Gallade
Gardevoir
Gastly
Gastrodon
Gengar
Grimer
Gulpin
Haunter
Kirlia
Koffing
Magcargo
Misdreavus
Mismagius
Muk
Ralts
Rotom
Shellos
Shuppet
Slugma
Spiritomb
Swalot
Weezing
Wobbuffet