A Colossal Challenge is the episode of Super 4 according to Netflix.
The episode starts with The Dark Baron drinking a potion from Forgusac to make himself larger. The heroes then talk about the tradition of returning the crown after winning tournament: you get the crown for winning, but you show your allegiance by returning it. Where Ruby comes from, if you win you get to rule. Alex explains that the Dark Baron tried to keep the crown last year.
After the king announces the start of the tournament, the heroes believe the dark baron will not compete because he did not show up, but someone in large armor shows up in the same armor as The Colossus and calls himself the Colossus as well. Alex believe he will not even have to compete because Sir Garith should win. Slyly, one of the dark Baron's men slips Alex a potion in his drink.
The man calling himself the Colossus start to win the tournament while Ruby and Gene wonder where Alex is ( and Twinkle thinks the Colossus will lose to every knight though he always wins. ) Even Sir Garith loses.
Gene ( and later the girls ) find Alex being really small. Twinkle explains it is a Widdle-Wegs Potion ( because now he has little legs. ) To kill time while they get Alex back to size ( trying to fix it mostly just caused Twinkle to mess up Alex's voice, ) Alex suggests Gene joust The Colossus, but Ruby steps up instead. While taunting the new challenger, the man dressed as The Colossus states his intentions to take the throne and to marry the princess ( she seems excited. )
While they joust, Gene is explaining a helmet with a camera mounted on it so Alex can help Gene duel. Once Ruby loses, Gene attempts to use the helmet to help him joust, but he loses too. Out of time, Alex shows up even though he is small. The King is reluctant to allow Alex to fight with his size, but tradition says that he should be allowed. Alex climbs up the armor and dashes around so he must swat at Alex like a fly until the man dressed as The Colossus hits himself enough to knock himself down. The Dark Baron's potion wears off and they see who he really is ( and his armor disappears. )
The king crowns Alex, and Alex returns the crown, but his voice is still messed up from Twinkle's magic. Twinkle tries to make it better but cannot.