Plasma Bulb

A plasma globe or plasma lamp (also called plasma ball, dome, sphere, tube or orb, depending on shape), is (usually) a clear glass orb filled with a mixture of various noble gases with a high-voltage electrode in the center of the sphere. Plasma filaments extend from the inner electrode to the outer glass insulator, giving the appearance of multiple constant beams of colored light (see corona discharge and electric glow discharge). 

Plasma globes were most popular as novelty items in the 1980s.

The plasma lamp was invented by Nikola Tesla[2] after his experimentation with high-frequency currents in an evacuated glass tube for the purpose of studying high voltage phenomena, but the modern versions were first designed by Bill Parker.Tesla called this invention an inert gas discharge tube

But these bulbs cause change in cell phone signals due to Radiowave Interference phenomenon

And Bringing a Zinc plate nearer to it may cause the plate to burn

These bulbs are not suitable for those who are wearing pacemakers

Source : http://en.wikipedia.org/wiki/Plasma_globe