Queen Chrysalis

The Changeling Queen Chrysalis is the main antagonist featured in A Canterlot Wedding - Part 1 and 2. She is a shapeshifter who took on the form of Princess Cadance in order to invade Canterlot by taking Cadance's place and render her husband-to-be, Shining Armor, unable to perform his duties as Captain of the Royal Guard.

Physical appearance
Queen Chrysalis is a changeling and thus a shapeshifter capable of taking many forms. She spends the entirety of A Canterlot Wedding - Part 1 and the beginning of A Canterlot Wedding - Part 2 in the form of Princess Cadance. Only the occasional flashes of her her own green eyes and the color of her magic differ from that of the Cadance's own.

Her true form looks like a pony with a twisted unicorn horn, a pair of insectoid wings and stands as tall as Princess Celestia herself. Unlike a pony however, she has coal black skin, a sharp pair of predatory fangs and dark green eyes with the pupils of a dragon. She has both a teal mane and tail, and also seems to have a greenish saddle, blue-green rib plate, and a small, black crown tipped with blue circles. Her voice has a doubled quality, as if two people were speaking in sync.

Personality
Chrysalis is shown to be a talented trickster and master of deceit. She fools Twilight's friends, Shining Armor, and even Cadance's aunt, Princess Celestia to believe that she was the real Princess Cadance. She only cares about getting what she wants and not who she hurts to get it, as demonstrated when she manipulates everyone to believe that she is the victim of Twilight not accepting her as her brother's future wife.

While capable to mimic Cadance well enough to fool most, she was unable to fool Twilight Sparkle for long. When Twilight attempts to do a special handshake of her and Candance's, she doesn't recognize Twilight at all, alerting her of "Cadance's" changed nature. She also acted rude and demanding toward Twilight's friends, in stark contrast to the real Cadance. Queen Chrysalis is cruel, uncaring and manipulative.