Sugilite is a cautionary tale. The fusion of Garnet and Amethyst, she is a towering twenty-foot giant of angry proportion. Sugilite carries Garnet's pride and confidence and Amethyst's devil-may-care attitude, creating a Gem Fusion powered by pure Id. She possesses little logic and rational thought and is instead driven by raw instinct.
When the Crystal Gems wanted to dismantle a disruptive Gem communication tower, Garnet suggested Sugilite to make quick work of it. Regrettably, she was too overconfident and failed to estimate how badly Sugilite would get. Sugilite was apathetic to the destruction she laid in her path, forcing Pearl to abandon her in favor of protecting Steven. For the latter, Sugilite left a strong impression; he wanted to emulate her to compensate for his physical weakness. Steven started a training regime and gradually became a demanding force of nature. This worried Pearl, who thought Sugilite's bad behavior was rubbing off on him. When Sugilite crashed Beach City, she stepped in to defend her home. Pearl was comically overmatched though; Sugilite made mincemeat out of her. Pearl was severely discouraged, but Steven started to root for her, having realized Sugilite was nothing more than a big bully. This gave Pearl the inner strength she needed to outsmart Sugilite and unfuse her.
Garnet only brought up Sugilite once more after that unfortunate incident, fueled by tranquil fury when Pearl took advantage of their fusion as Sardonyx. Otherwise, she knows better than to open Pandora's Box again, leaving Sugilite currently in the backburner.