Little Green Man (Gravity Falls)

The Little Green Men are an unnamed sapient race of aliens that remain secretive from humans thus if wherever exposed, they will potentially commit suicide by consuming a cubic pill.

Biology
They're lilliputian glutinous creatures with only a pair of forelimbs and have large red eyes. They were black gloves and a belt labelled with lightning bolt emblem.

History
A small of little green men were shown to operate a robot disguised as a human resident in Gravity Falls, Oregon which always faced left. When Dipper and Mable Pines exposed them, they immediately commit suicide.