Small amphibious creatures which stand about two to two and a half feet tall that go around about the world wreaking mayhem. Similar to the Gravelings in 'Dead Like Me, but don't look to create imminent death as much as minor misfortunes and strong negative emotions.
Strongly resembling a bizarre mixture between Whammy's and Gremlins fed after midnight- they zoom around guised in shadows, and can only be seen by the very emotionally unstable.
Grebblies also are likely to devour current thoughts making you forget what you are doing at the current moment, and generally prone to ruin consecutive days.
Be cautious of their tail because the tip is barbed with a powerful negative neuro-toxin.
For some reason I just want to punch someone in the face right now... I must have got stung by a Grebblie.