An F.O.E taking the form of a large pteradactyl with heavy makeup and golden hair, it roams all over Junessic Land save for the third floor, where only Tyranniqueen will appear in order to make way for an event.
It is an F.O.E that spends most of its time patrolling a fixed route in the air searching for prey, and can pass through walls due to its airborne nature. It appears as a large shade on the ground and will attack instantly if the party approaches its Shadow.
It usually attacks with regular attacks, although it can cast Wind Dance and Tentarafoo. It is susceptible to most status conditions and is especially vulnerable to sleep, although paralysis and curse will be less effective. It is weak to ice, and resists bless and curse.
It was later revealed that Seidoptera is a Cognition of the bullies in Hikari's secondary school who defaced Miyuki's desk. When Hikari helped Miyuki clean her desk and befriended her, the bullies target Hikari as well, which indirectly caused her exile as she tried to act as a voice of reason when her friends are about to kick Miyuki out of their friend group and all of her friends including Muyuki distanced themselves from her due to disagreeing with her opinion.
Despite being set up as one of the main villains of the movie, it is merely one of the F.O.Es roaming the labyrinth, unlike the Herbivore Dinosaurs that act as the labyrinth's boss. This indicates that the very ones who caused Hikari's trauma are not the bullies, but her friends who decided to distance themselves from them by lynching anyone who fell victim to them.