To dance around and sing the "scadoo song" then jump and land into a 2d picture or object. This is usually done when people want to flee the police or when cute host-people want to follow there talking dogs into paintings for educational adventures.
Blue scadooed we can too! *dances obnoxiously and leaps headfirst into painting*
You are playing Halo with the guys and you set up for a sniperkill, as you pull the trigger you say with a hint of coolness, "Scadoosh!" as they die. This can be followed by a victory dance or whatever you so please.