Lava Lamp

The Lava Lamp is a transparent electric lamp containing a viscous liquid in which a brightly colored waxy substance is suspended, rising and falling in irregular and constantly changing shapes.

Uses
In older games this object could be used to illuminate dark levels. It also worked underwater, making it quite useful.

Since dark levels were removed in later games, a new feature was added. Clicking on this object gives a Turn On/Off option, selecting it makes the lamp emit a purple light effect.