Four Arms

Four Arms is a Tetramand(a play on latin "tetra" meaning "four" and "mand" meaning "arms") from Khoros. He is the sixth Omnitrix alien to appear on the series. He first appeared in Washington B.C. when Ben needed to fight the giant mammoth that Dr. Animo reanimated.

Appearance
Four Arms stands at approximately twelve feet in height, has very well developed muscle, four-fingered arms with two on each side, and had the Omnitrix symbol on the upper-left shoulder during the original series. His skin is bright red and very tough, like it is armored. A black stripe goes from the bridge of his nose to his neck(and possibly down to his entire spine). A second black strip goes from his chin to his lower lip, and he has four eyes: a main pair, and a smaller pair below them. And he looked like an ogre in the past.

Abilities
Four Arms possesses tremendous superhuman strength, nearly limitless endurance, and thick skin. His strength is such that he can create shockwaves simply by smashing the ground or clapping all four hands together, dubbed the "Big Smack". Four Arms' muscular legs also allow him to leap several city blocks at a time. As shown in Ultimate Alien, Four Arms is strong enough to hold a car on each of his lower hands. He is one of the several aliens in the Ultimatrix(as well as Humongousaur, Way Big, Cannonbolt) whos basic power is super strength.

Weaknesses
Sometimes Four Arms' bulk is a disadvantage, since the Tetramand species sacrifices speed for strength and cannot run for long distances or at great speeds. Fourarms' size also makes him unable to hide anywhere or sneak behind anyone.

When Ben had a cold, Four Arms turned orange and had stinky hives. Strangely, when Ben tries to change into Four Arms, the Omnitrix seems to nearly always change into a different alien. This may be the AI of the Omnitrix, which uses more strategy than Ben, who simply liked smashing things. In the episode side effects ants were crawling all over him and kept on scratching and control himself and started crashing into the wall.

Gwen 10
Gwen used Four Arms when she and Ben snuck into a bowling alley, throwing strike after stike, though due to the increase of her strength, the bowling balls that Gwen threw crashed through the pins and into the back wall.

Ben 10: Ultimate Alien
thumb|right|200px|Fourarms transformation in Ultimate Alien Four Arms reappeared in Ben 10: Ultimate Alien episode, Video Games, shown turning Ssserpent into a sandwich between two cars. He appeared again in Escape From Aggregor, where Ben used him to fight against the Yeti which was controlled by Dr. Animo. He also appeared in the episode Hero Time, facing Captain Nemesis in a game of Tug of War and won. He looks almost entirely different, appearing more like a gladiator. He now has the Ultimatrix symbol on his chest. He now has no shirt, which is replaced by two gold sashes that cross over his torso. His pants are also gone, replaced by a pair of brief, black underwear and a gold belt. He doesn't have gloves anymore, and has gold braces on each wrist and ankles. His face is also more narrow, resembling that of Manny Armstrong. This look makes him look more like Tini, a Galactic Enforcer of the same species as Fourarms, only with the black strip on his head, due to that Tetramand females lack the black facial markings. His head stripe also now ends in the form of a ponytail perhaps because, his head stripe might be actually hair(which would give male Tetramands a natural beard at childhood because, of his chin stripe). Even in Gwen 10, Gwen has red hair instead of stripes. Fourarms now has green eyes rather than yellow eyes, just like all reappeared aliens.

Possible future
His Ben 10,000 form has a better developed forehead, more muscle mass, no sleeves, and a pair jutting incisors. He has thicker skin. The Omnitrix symbol has moved to his chest probably because he can not reach it to change or maybe it does not fit on the arm anymore. Four Arms still has his kind of gloves and pants. He also has three curved spikes on each arm and one small spike on his shoulders.

Ben 10

 * Washington B.C.
 * The Krakken
 * Tourist Trap
 * Kevin 11
 * The Alliance
 * Lucky Girl
 * Side Effects 
 * Secrets
 * The Big Tick
 * Framed
 * Gwen 10
 * Grudge Match
 * The Galactic Enforcers
 * Ultimate Weapon
 * Tough Luck
 * Ghostfreaked Out
 * Back With a Vengeance 
 * Ben 10,000
 * Game Over
 * Super Alien Hero Buddy Adventures
 * Under Wraps
 * The Unnaturals
 * Monster Weather
 * The Visitor
 * Perfect Day
 * Don't Drink the Water(Young Version)
 * Ready to Rumble
 * Ken 10
 * Ben 10 vs. the Negative 10 (Part 2)
 * Ben 10: Secret of The Omnitrix

Ben 10: Ultimate Alien

 * Video Games
 * Escape From Aggregor
 * Hero Time

Ben 10: Protector of Earth
Four Arms is the first alien you will need in the game to battle drones and bosses. You will need him to fight evil and moving objects. He also has a unlockable Dark Heroes and DNA Force skin.

Ben 10 Ultimate Alien: Cosmic Destruction
Four Arms will be an additional alien for cosmic destruction. If you have a PS3 you will fight evil with Four Arms. Four Arms is only playable on PS3.

Trivia

 * Four Arms is Ben's favorite alien form to transform into in the original series, and he still uses this form in Ultimate Alien.
 * In Cartoon Network's online game Fusionfall, he is known as a nano.
 * The black stripes on Four Arm's face in the original series have been converted into a small goatee and a ponytail in Ultimate Alien. In The Galactic Enforcers, Tini's hair was like Four Arms' with the stripe being the start of the hair.
 * He is the first known alien to barf as shown in Washington B.C.
 * It is shown in Ultimate Alien that Ben didn't know Four Arms was still in the Ultimatrix, seeing as when he fought Serpent for the second time in the series and transformed into him, he said, "Four Arms! Whoa, didn't even know that was still in there!".
 * In both series that he appeared in, he was mainly facing off against Dr. Animo.
 * Four Arms is the first alien with four arms, the second is Spidermonkey and the third is AmpFibian.
 * His Ultimate Alien appearance is similar to Kintaro from Mortal Kombat.
 * In the original series finale, some kid at Ben's school called him "Quad Hands".