Invent the new worst/most useless chess piece ever!

ligma, when triggered will say LIGMA BALLZ covering the opponents screen making them unable to move for 10 seconds, costs 20 bits (bits obtained from winning games)

Annoying square changer - change light squares to dark squares before the first move so you can't tell the difference between squares.

That sounds like a Tungusta meteorite.

The taxi moves and has a shape like a rook but cannot capture anything but it instead picks up a random piece nearby and moves it into random square.