Steven Universe

Steven Universe is a 2013 animated series created by Rebecca Sugar for Cartoon Network. It follows the adventures of Steven Universe, a half-human, half-alien hybrid living with a trio of magical aliens called the Crystal Gems as he learns to manage his powers.

Cat Fingers
Season 1, Episode 6 Airdate: November 25, 2013

The Purple Puma makes his first brief appearance as Amethyst is demonstrating her shapeshifting abilities to Steven by rapidly shifting between a myriad of different forms - one of them being The Purple Puma.

Tiger Millionaire
Season 1, Episode 9 Airdate: January 20, 2014

Amethyst's wrestling alter ego "the Purple Puma" is revealed, where she turns into a muscular male looking character.

Ocean Gem
Season 1, Episode 26 Airdate: September 25, 2014

Purple Puma makes an appearance once again.

Garnet's Universe
Season 1, Episode 33 Airdate: November 13, 2014

"While training to beat the Foxman, Garnet can be seen lifting her weighted gauntlets. She can be seen with bulging biceps whilst also struggling to attempt to lift her gauntlets."

Maximum Capacity
Season 1, Episode 43 Airdate: February 26, 2015

Amethyst shapeshifts Purple Puma makes a very short appearance in this episode.

Reformed
Season 2, Episode 5 Airdate: April 30, 2015

Amethyst regenerates to have huge muscles in order to take on the monster.

Log Date 7 15 2
Season 2, Episode 26 Airdate: January 8, 2016

Hit the Diamond
Season 3, Episode 5 Airdate: June 2, 2016

She shows confidence towards her enemies (threatening the Crystal Gems that she will tear them "limb from limb"), and support to her allies, demonstrated when she angrily explains Ruby she did not swing the baseball bat correctly in "Hit the Diamond" and flexing and yelling "YEAH" when Ruby seemingly does it right.

She then takes the bat and hits the ball hard, getting a home run. "Army" runs the bases like a soldier. When the Crystal Gem Ruby later hits the ball, "Army" runs over cheerfully and flexes her arms.

Screenshots

Steven Floats
Season 3, Episode 6 Airdate: July 18, 2016

Steven vs. Amethyst
Season 3, Episode 19 Airdate: August 3, 2016

Pool Hopping
Season 5, Episode 15 Air date: March 26, 2018 (CN App); April 23, 2018 (TV)

Garnet takes up a job at the Big Donut in an attempt to be random after her Future Vision is starting to lose power, but quits almost immediately, ripping off her uniform with one giant flex.

Homeworld Bound
Season 6, Episode 17 Airdate: March 27, 2020

Yellow Diamond is now able to permanently change physical forms with her electricity powers, and demonstrates this on Spinel, making her arms big and her feet little.

Gem Karaoke
Short #8 Airdate: October 3, 2016 (iTunes) Airdate: September 2, 2019 (TV)

Amethyst: You're a karaoke beast! [flexes arm muscles]

Dove Self-Esteem Project
 Appearance Related Teasing and Bullying 

Amethyst and Jasper talk about accepting who you are.

Steven Universe Comic #1
Amethyst makes fun of Pearl by shapeshifts into a gigantic and muscular version of her.