Quoted By:
>Sugimori: “These two were created during the latter half of development, after an order came in for a dual-type Grass and Steel Pokemon. Ferroseed and Ferrothorn were designed by the same person as Foongus and Amoongus. The planners proposed the design be something like those seeds that sometimes stick to your clothes. We had the idea that large groups of these Pokemon would stick to rock faces.”
Just spiky seeds that stick to things