The basketball. Shoot it to the HOOP piece (you gotta click a perfect timing on a sliding bar) and if you make it... You get an extra rook or knight it is your choice (hoop piece doesn't move it's immobile unless blocking check (basketball and hoop is illegal to capture)
create the most stupid chess pieces!

The Non-Queen. If you capture a piece by the Non-Queen, you lose the Non-Queen but not the piece you capture. Also, after you play, your Elo is -100. So if you win but you capture a piece by the Non-Queen, you lose. Get it?
The One-gogoolplex-and-thirty-four-tailed monkey. You can move it during the opponent’s turn, and if it captures something, you win, and if it jumps over a piece, all pieces of that sort dissapears, and if it moves at all, you get a new queen anywhere, and if the opponent captures it, you win; but it simply doesn’t move.


Sheldon - every time you make a bad move the player with the Sheldon can give the piece 1 strikes if the piece exceedes 3 strikes it is eliminated
The killer knight. If you capture it, your king dies.