Krackenstein

Krackenstein is the evil robot made by Willem Viceroy to destroy the ninja in "Last Stall on the Left". He returns in "To Smell and Back" only to be defeated again.

Krackenstein has 6 arms (Crab arm, Robot Arm, Octopus Arm. etc) and 1 arm on its chest

Trivia

 * His name is obviously a play on Kraken, a mythical giant sea squid, and Frankenstein, or rather Frankenstein's monster, a sort of robotic man.
 * When McFist said "Release the Krackenstein!", this quote my have been a play off of the quote, "Release the Kraken!" from the movie Clash of the Titans.