"It is the physical form of sickness and rot; a walking disease. Cure it."
That the Worm Keepers held within the Prison of Elders would even attempt such a delicate metamorphosis so far removed from the full resources of their Summoning Pits speaks to either desperation or madness.
Challenge the Worm Keepers and cure the Prison of the hulking sickness they have birthed, or drown in the bile and mess of a festering abomination.