Ia’Affrat can occupy another creature’s space

and vice versa, and the swarm can move through any opening

large enough for a Tiny insect

Ia’Affrat can enter the body of an incapacitated or dead creature by crawling into its mouth and other orifices. Inhabiting requires 1 minute, and the victim must be Small, Medium, or Large. If Ia’Affrat inhabits a dead body, it can animate it and control its movements, effectively becoming a zombie for as long as it remains inside. Ia’Affrat can abandon the body as an action. Attacks against the host deal half damage to Ia’Affrat as well, but Ia’Affrat’s resistances and immunities still apply against this damage. In a living victim, Ia’Affrat can control the victim’s movement and actions as if using dominate monster (save DC 19) on the victim. Ia’Affrat can consume a living victim; the target takes 5 (2d4) necrotic damage per hour while Ia’Affrat inhabits its body, and Ia’Affrat regains hit points equal to the damage dealt. When inhabiting a body, Ia’Affrat can choose to have any spell it casts with a range of self, target the inhabited body rather than itself. The skin of a creature inhabited by Ia’Affrat crawls with the forms of the insects inside. Ia’Affrat can hide this telltale sign with a Charisma (Deception) check against a viewer’s passive Insight. A greater restoration spell or comparable magic forces Ia’Affrat to abandon the host.

Ia’Affrat has advantage on saving throws against spells and other magical effects

Ia’Affrat is shrouded in a 5-foot-radius cloud of dark smoke. This area is lightly obscured to creatures other than Ia’Affrat. Any creature that needs to breathe that begins its turn in the area must make a successful DC 16 Constitution saving throw or be stunned until the end of its turn.