Eye-plant
From Tardis Wiki, the free Doctor Who reference
Eye-plants are plants native to the planet Spiridon.
The bud that projects from the side of this plant is capable of detecting motion and will slide from side to side to keep an object in view. It is the only know species on Spiridon known to be able to detect the otherwise invisible Spiridonians, which makes it invaluable as an early warning to their approach. (DW: Planet of the Daleks)
