The high-powered magnifying glass is a convex lens that only appears in the episode "Spy Buddies." It is invented by Sandy, who gives it to SpongeBob and Patrick when they become spies.
The high-powered magnifying glass resembles an ordinary magnifying glass.
Role in episode
SpongeBob and Patrick use this item to see things very close up. When they use it on Plankton, a sun-beam passes through the magnifying glass, which becomes increasingly hot, thus setting Plankton on fire.