These devices are a type of enormous electrical battery which supply Castle Heterodyne with its emergency backup power system. There are enough of them in The Great Movement Chamber under the Castle to keep the structure's fractured intelligence(s) active and semi-alert from the time it is attacked by The Other until just before the Siege of Mechanicsburg, although by the latter time they are nearly completely drained. Agatha and Co. to power their cure of Agatha, Gil and Tarvek's joint case of Hogfarb's Resplendent Immolation, and later Agatha them by deploying Gil's "Zappy Stick" on the lightning rods on the roof of the Castle.
In the comic proper they are never named or described at any length, but the print novel Agatha H. and the Voice of the Castle includes a longer discussion of the subject. Archeologists have unearthed the corroded remains of an ancient variation of them in an unnamed tomb, with a date of creation estimated to be somewhere between 250 B.C. to A.D. 500. Tarvek says he has done a thesis on them, and thus knows that their red lights are a sign of how drained their power-levels have become.
- ↑ Footnote Number 86 on page 402 of the hardback edition