Cannot move.
Gain +2 DEF. Can counterattack.
Enemies who move into the same panel must battle you.
Effect
Flying Castle's Hyper is Immovable Object. Upon use, the player will instantly end their turn, as well as skip their next turn. For two chapters, the player gains +2 DEF, and any unit that passes the panel the player is on is forced to challenge them to battle. If the player is Flying Castle, it also allows them to counterattack.
Since this card forces players to select Yes to challenge prompts, units that cannot challenge players on the field due to a character passive or stock effect will bypass this effect.
Strategy
Immovable Object effectively entrenches the player on a panel and renders them unable to move for 2 turns. This can help to lose opponents that are incessantly attacking from the rear, or enable you to KO them. Unsurprisingly, this Hyper helps dramatically for KOing low health characters and for escaping high-attack characters that could potentially deal a lot of damage.
As the Hyper boosts DEF by +2, gives Flying Castle the ability to counter-attack, and forces any enemy that passes its panel to battle, the Hyper opens a window for Flying Castle to take revenge on opponents.
The main downside of the Hyper is that depending on the opposing player's rolls, an opponent might not even roll into the player's space before the Hyper's duration ends. This problem is further worsened if the board is large and has multiple alternate paths, as the opponent may simply walk or warp around the player without entering combat.