In the video game Suicide Squad: Kill the Justice League, there is a scene where King Shark temporarily becomes a Green Lantern and manages to use his Green Lantern ring to create a huge shark-shaped construct that breaks through the enemy ship’s shield.
But then, King Shark seems to lose his mind and turns the shark construct against his own Suicide Squad teammates. They have to wrestle the ring off his finger to stop his rampage, and only then does he return to normal.
Video of the scene (relevant part starts at the 3:35:40 timestamp):
What was going on here? I don’t know much about Green Lantern (or King Shark) lore. How did the ring affect King Shark’s behavior? Why did he suddenly attack his allies with the ring’s power?