Dr. Arthur Light is a recurring villain from Teen Titans Go!. He is an evil man with a robotic suit, that comes equipped with light-based superpowers. He has tried many times to destroy the Teen Titans and consistently failed, mainly on account of his oafishness. More often than not, Dr. Light has been a friend to the Titans rather than an enemy.
Dr. Light made his first appearance "Staff Meeting", where he faced off against Robin in a fight. Robin's staff was broken, making it a laughably pathetic weapon to fight him with. Just as one would predict, Dr. Laugh began pointing and laughing at Robin's staff as the latter helplessly tried to beat him down with it. Dr. Light eventually blasted a giant beam of light from his hand, terminating Robin completely.
Dr. Light returned for a more major role in "Colors of Raven" when he stole a diamond from a museum. He enjoyed this diamond immensely because it could reflect his light and make it more powerful. The Teen Titans arrived on the scene and put a stop to his evil deeds. Although Dr. Light was dealt with, the crystal the Titans obtained after the battle still gave them trouble, when they used it irresponsibly.
Dr. Light made his next appearance in a far more centric role in "Caged Tiger" when he constructed a giant doomsday device, which he planned on using to destroy the Teen Titans. Unfortunately for him, Robin, Cyborg, and Beast Boy all got stuck in the broken elevator, so he had to wait a while with Starfire and Raven before he could finally destroy all of them together as he initially planned.
While waiting for the boys, Raven was curious and asked Dr. Light how his invention worked. Dr. Light lit up when Raven asked him about himself and he showed her the ropes. Starfire and Raven actually took an interest in his invention and Dr. Light took an interest in their lives too, asking them about how it is to live with the boys. Before they knew it, the three of them were hitting the town and spending time together as friends, doing a happy montage full of friendly activities.
After this life-changing experience, Dr. Light admitted that he was enlightened by Starfire and Raven, saying that now he plans on giving up his evil ways and becoming a good guy from then on. Starfire and Raven were so glad to hear that Dr. Light was now good. However, just then, Robin, Cyborg, and Beast Boy finally showed up on the scene, having gotten out of the elevator and without thinking, they all beat Dr. Light senseless.
In "I See You", Robin and Starfire went on a stakeout mission and found out that Dr. Light was building a collection of crystal chandeliers. Dr. Light named all of his chandeliers after phrases like "The Pain of Defeat". This seemed like an innocent hobby at first. In fact, Dr. Light was being very neighborly, welcoming them into his lair and telling them about what he was doing. However, it soon turned out that this was all part of his master plan to build a giant light cannon and use the crystal chandeliers as prims, to reflect the light all over the place. Starfire, (who at the time, was cosplaying as a man named "Jeff") knocked all of the chandeliers off the ceiling, leading to Dr. Light getting crushed by The Pain of Defeat.
In "Man Person", Dr. Light fought with the Teen Titans and used a light beam against them. Beast Boy had previously gotten a scar from a fight with Cinderblock, which made him look really cool. He wanted to make himself look even cooler, so when Dr. Light shot a beam of burning light at them, Beast Boy intentionally stuck his hand in there, burning it off, so that it would get replaced by a cool robot hand.
In "Cat's Fancy", Dr. Light placed a giant time bomb in the middle of Titans Island and it was really close to exploding. The Titans were unable to defuse or destroy it and the clock was ticking so they had to think fast. Starfire had the ability to lift it up and she used a speed burst to fly the bomb into outer space, where she planned on throwing it out of range. However, the time on the bomb ran out before she could ditch it, leading to herself getting caught in the explosion. She plummeted back to Earth and crash-landed into the ground, leaving a crater there. The Titans worried that she had died, but thankfully, she was only unconscious.
In "The Streak", Dr. Light robbed a bank. Robin, Sticky Joe, Santa Claus, Beast Boy, and The Tooth Fairy showed up to defeat him, but they were all really incompetent heroes. Dr. Light thought he could get away with his crime, due to his competition, but just then, Kid Flash showed up and kicked the crap out of him.
Dr. Light is obsessed with lights, prevalent by the fact that he's based his entire supervillain persona around the element. Despite being a light-themed supervillain, Dr. Light isn't all that bright. In fact, his stupidity is the number two cause of all of his failures, second only to the obvious Teen Titans. Dr. Light is also one of the most friendly of the villains, as he's shown a bright side to his evil personality. In "Caged Tiger", he became the best of friends with Starfire and Raven. In "I See You", Dr. Light saw the Teen Titans come into his house and he happily greeted them as he showed them the crystal chandeliers he was building. In "Lication", Dr. Light paid to borrow Robin's motorcycle. Unfortunately, in all three of these instances, Dr. Light's goodness was not rewarded. Rather, he would be beaten up by various members (if not, all members) of the Titans either for very arbitrary reasons or for the Titans misunderstanding his good intentions.
- In "Caged Tiger", it was revealed that his real name is "Arthur".
- He is one of the many villains to appear in "Teen Titans Go! to the Movies", along with Slade, Jinx, Control Freak, Mad Mod, Mumbo Jumbo, and Gizmo.