In the series, Arthur, Lancelot and other playable characters may be temporarily transformed into something else by evil magic. The Magician is the most common source of transformations, but it may also be caused by other hazards and enemies, like Rangda and Hell Face.
The Magician's power can transform Arthur into a frog.
- Baby - Arthur's transformation when he is without armor.
- Seal - Arthur's transformation with the Steel Armor.
- Bee - Arthur's transformation with the Bronze Armor.
- Girl - Arthur's transformation with the Golden Armor.
- Small Fry - Arthur is shrunken down. In this form, he can't use magic, double jump, and pickup items. Also, his attack power, agility and jump height are reduced.
- Beanpole - The inverse of Small Fry, Arthur is elongated, making him an easier target. Arthur can't use magic powers, double jump (although he jumps higher in this form), dash and pickup items.
- XL Woman - Arthur is turned into a portly female villager. Arthur is unable to use magic powers, shields, double jump, and pickup items. Also, the agility is reduced, and the woman's skirt makes Arthur glide slowly while in the air. While this can be useful to pass large areas, the woman's low speed makes Arthur an easy target to flying enemies.
- Skeleton - Arthur becomes a skeleton that can't double jump and dismantles with each jump, requiring some time to reform and move again.
- Chicken - Arthur is transformed into a desperate chicken that can only run and jump.
- Grasshopper - Arthur becomes a large grasshopper that can only run and jump, but faster and higher than the chicken.
- Moth - A rare transformation that changes Arthur into a large moth that can only fly around. While limited, it is useful to reach high areas.