Splinter Twin is a blue/red combo deck for the Modern format (as of Jan 18th 2016, Splinter Twin has been banned in Modern format, rendering this deck unplayable). It primarily aims at putting a creature with an Untap ability onto the battlefield, either Deceiver Exarch or Pestermite, then copying it either with Kiki-Jiki, Mirror Breaker, or enchanting that creature with the namesake Splinter Twin and giving it the ability to copy itself. Each copy put into play again untaps the creature that generated the copy. Thus a near infinite number of creatures can be put into play. All of those copies have haste and can immediately kill the opponent.
Patrick Dickmann won Grand Prix Antwerp 2013 with the following Splinter Twin deck: