Jellyfish Motion Lamps

A jellyfish lamp is a sealed tank of liquid with soft artificial jellyfish inside, lit from below or behind and moved by a small pump or motor. The jellyfish drift, turn, and rise in a loop while the light cycles through colours. No jellyfish are involved, and nothing living goes anywhere near it.

How a jellyfish lamp differs from a wax lava lamp

Both lamps sell the same thing, which is slow hypnotic movement, but they get there in completely different ways.
A classic lava lamp is driven by heat. A bulb warms wax until it becomes buoyant enough to rise, then it cools and falls. That means a warm-up period, a limit on how long you can run it, and a lamp that gets genuinely hot.
A jellyfish lamp is driven by water movement, usually from a small pump, with the light supplied separately by LEDs. That difference has practical consequences: there is no warm-up wait, the lamp runs much cooler, and most models will run for longer stretches. It also means a jellyfish lamp usually has a motor, so it makes a faint sound where a wax lamp is silent.