|“||How messed up is that? That I've gotten away with this for so long, you have no idea how bad I am! You think I'm so great, I'm so mature, and I always know what to do, but that's not true! I haven't learned a thing from my problems. They've all just made me worse! You think of me of some angel but I'm not that kid anymore! I'm a fraud... I'm a fraud... I'm a MONSTER!||„|
|~ Steven moments before turning into a monster.|
|“||White Diamond: Wai- OH!
Yellow Diamond: White!
|~ White Diamond merging with Steven's new perception.|
Monster Steven is an enormous hot-pink humanoid saurian or wingless draconian creature with white-pink spikes protruding from his back and elbows and four spikes on his face, two of which are like tusks and the other two like horns. He has a hunched back and muscular build with an armored crustacean-like carapace, a potbelly with his gemstone where his navel would be, digitigrade arms and legs with five dark pink claws on the end of each and a short tail with two more spikes. His face has a pig-like nose, dark eyes with small pink pupils and a mouthful of sharp teeth.
As a combination of his increasing mental instability and uncontrollable new strength, Steven reaches his final emotional breaking point, seeing himself as a hollow shell of the joyful, caring and innocent peace-bringing child he was. After his breakdown it is revealed that if Steven believes himself to be a monster he can actually become one. He is then reduced to a mindlessly feral creature intent on causing destruction out of his overwhelming anguish; in this state he does not listen to anyone and will ruthlessly attack those who try to stop him without hesitation. Despite this the real Steven is not completely gone as enough positivity and compassion from his loved ones can soothe his rage, effectively causing him to return to normal.
When Steven is confronted by his closest peers he is prodded for information about his problems with it being learned that Steven never told anyone else about a recent visit to the hospital or other events; after Steven admits to everything including his intentional shattering of Jasper and attempted destruction of White Diamond to everyone's shock, he finally snaps completely, claiming to no longer be the person he was during the time of the Homeworld Gems and openly denouncing himself as a monster before actually turning into one, demolishing the house with his transformation.
Once Steven goes on a rampage and damages the Crystal Temple, also threatening to destroy Beach City and Little Homeworld his friends try to restrain him; the Great Diamond Authority and Spinel then arrive and are shocked when told about Steven's condition. Both Yellow and Blue Diamond try to remold his form and feelings with their new powers and White Diamond attempts to connect with Steven using hers only to collapse due to his fury. Steven soon frees himself from Lapis Lazuli's chains by letting out a roar that pushes everyone back, even causing Garnet to unfuse. When the Cluster joins the fray Steven is able to knock it out after a short struggle. However, Steven's love interest Connie Maheswaran rallies everyone and says they have to show Steven compassion as he once did with them.
The Gems and his father Greg Universe then give him a hug and explain how Steven helped them overcome their own difficulties and they'll also be there for him after which Connie gives him a kiss, snapping him out of his anger and making him shed tears that return him to normal.
- Superhuman Strength: He was able to destroy several parts of the Crystal Temple and unfused Alexandrite with one hit. Even though he was restrained by Lapis and then the Cluster he released himself almost effortlessly.
- Superhuman Durability: One of his horns could withstand blows from Bismuth's enhanced shapeshifting.
- Willpower: Steven was able to power through and tank almost everything thrown at him due to the will he inherited from his mother and humanity he inherited from his father.
- Magic Immunity: Due to his raw emotions and hybrid status, Steven could partially resist even the abilities of the other Diamonds, being relatively unfazed by Yellow Diamond's light destabilization and Blue Diamond's pathokinesis, additionally overwhelming White Diamond's mind control.
- Shapeshifting: Since Steven turned into a monster due to his thoughts of being one, it was clear he kept this ability. It appeared that as time passed Monster Steven decreased in size; this could be seen that after appearing as tall as the Crystal Temple, he later looked only a few meters taller than the Diamonds.
- Water-Walking: He was capable of moving and standing on liquid surfaces as seen when charging against his friends and family; this is something shared with his pet Lion and numerous other Gems.
- Gem Half/Pink State: Since Steven transformed while in the state of his Gem half, it is possible he kept the abilities while this form was active and could be the reason he gained the power to truly challenge the Diamonds and turn into a monster in the first place.
- Sonokinesis: After charging himself up which resulted in his spikes and eyes glowing pink, Steven could let loose a roar that managed to send everyone within range flying to the point Garnet unfused into Ruby and Sapphire. The attack also created a shockwave that pushed away the ocean and cracked the ground surrounding him, even knocking over the incomplete Diamond Mech and awakening the Cluster. This could be a stronger version of Steven's scream when tapping into his mother's original powers.
- Healing: After being embraced by his family and friends Monster Steven began crying and caused the water around him to turn pink, which could be attributed to Steven's ability to heal or resurrect Gems and other living beings.
- Intelligence: After becoming a monster, Steven seemed to be reduced to a mindless creature that attacks and destroys everything. This was shown when he fought recklessly instead of formulating a plan, only made animalistic sounds and didn't use his original or complex abilities.
- Emotional Manipulation: Since his transformation is the result of Steven's negative emotions, it is clear positive ones can work against him. This was used to make him understand that since he was there for everyone he cared about, they loved him unconditionally and would return the favor, which resulted in Steven remembering everything and turning back to normal.
- Monster Steven is the final antagonist of Future and could be considered the final antagonist of the entire series.
- Steven's monster form resembles Godzilla, DC Comics' Doomsday, the Deathclaws from Fallout and Killer Croc from Batman: Arkham Knight. It is also likely a reference to Marvel Comics' Hulk and anime characters turning into figurative or literal monsters while his pink state is a reference to video game power-ups and anime characters assuming more powerful forms.
- His transformation was foreshadowed a number of times:
- During the original series Steven would be shown struggling to cope with stressful experiences, especially if they were somehow related to his mother's past. It was even implied that the discovery of her deceptions and his confrontations with their victims further attributed to Steven's failing grasp on sanity and reality.
- When Steven first appeared as a monster in the opening of Future, there was a pink glow in his eyes which is related to Pink Diamond, but the monster was purple due to being in shadows. Also, the background was noted to be similar to the appearance of the sky in Steven's mindscape.
- The issues and circumstances leading up to and surrounding Steven's transformation paralleled the ones he had helped others with:
- Monster Steven being hugged by Garnet and the others is a callback to Steven comforting a corrupted Nephrite.
- Garnet mentioned how she literally fell apart and he was there for her and her components.
- Amethyst mentioned how she never loved herself, but he showed her otherwise.
- Pearl mentioned knowing what it was like to keep a part of herself secret.
- Peridot mentioned how he never gave up despite her efforts to undermine him and the other Crystal Gems.
- Aside from the potential fully-formed Cluster, Monster Steven is the most powerful character in the series as shown by the partial Cluster and Diamonds failing to stop him.