Tachyon pulse inverter

A tachyon pulse inverter was an item of technology that involved tachyons.

In ancient Egypt, an escaped alien criminal planned to harness the Nile's kinetic energy to power a tachyon pulse inverter. Its activation would have ignited Earth's atmosphere and burned half of its surface. The alien's plot was thwarted when the Eleventh Doctor recaptured it. (IDW: Assimilation²)