A well-working lava lamp requires an incandescent bulb that heats the bottom of the bottle, where a closed ring spring forces the lava to spread over the entire bottom, what causes the heat to propel it into eruptions. The proper adjustment of the equilibrium temperature, so that the wax falls down regularly, is also quite complex.
The light can be provided by LEDs, the real problem is this homogeneous and transparent heat source.
But precisely this challenge can allow an energy optimization and at the same time allow to transform into custom lava lamps glass containers with original shapes.
In the principle it only means to stick some heating element (coil of resistive wire ?) on the glass and provide some current regulation, maybe driven by a temperature sensor... This could be worth a summer circuit.
Then it can become more sophisticated and anyway it is more than only pure electronics.
Do you like it ?