The Fever Mode is one of the base concepts of the game. When in Fever Mode, the Combo Worm will become a red colour, now becoming a Fever Worm. In Patapon 3 , it has a spikier appearance and it will gradually fill up with a golden colour, indicating that you can now Summon a Djinn. Fever Mode has much more complicated and nicer music and sounds than when you aren't in it.