Queen Chrysalis is a G4 character. She is not a pony, but is of a species known as Changelings, insect like creatures that appear vaguely pony-like but have holes in their bodies. She was initially exclusive to the TV show My Little Pony: Friendship is Magic before being introduced into merchandise.
Queen Chrysalis appeared in the episodes A Canterlot Wedding: Part 1 and A Canterlot Wedding: Part 2. She is part of a race known as Changelings and serves as their queen. Changelings have the power to transform themselves into a pony, and absorb the love other ponies have for that pony as food. For most of the episode, Queen Chrysalis uses this ability to appear as Princess Cadance, whom she had imprisoned. Using her power to feed on the love of Cadance's fiance, Shining Armor, Queen Chrysalis attempted to gather the power to take over Equestria and feed on the love of its citizens. She is eventually defeated thanks to a powerful spell cast by Shining Armor and Princess Cadance.
The Changeling Minions are the henchmen/servants of Queen Chrysalis. Like her, they have the power to transform into ponies and feed on love.
Queen Chrysalis was included as a card in the Enterplay Trading Card collection.
My Little Pony Favorite Collection
Queen Chrysalis was included in the second edition of the favorites collected. Her mold is based off of Princess Celestia's, with stickers attached to represent the holes a Changeling body possesses.