You found a Kakuna!

From Wikipedia, the free encyclopedia

Kakuna (コクーン Kokūn, Cocoon), known as the Cocoon Pokémon, are pupal Pokémon found in the Kanto and Johto regions, of which its larval form is the worm-likeWeedle. They can evolve into the hornet-like Beedrill. Kakuna is a yellow, cone-shaped cocoon Pokémon. Kakuna has a dome-shaped head and black, triangular eyes. Within the shell, a Kakuna busily prepares itself for evolution into its adult form, and the amount of energy released by this process makes the shell hot to the touch. Kakuna can use a poisonous sting to defend themselves if disturbed.