Grasp of Orcus
Glabbagool is is the slowest, and slimiest, ally of the party.
Glabbagool is a gelatinous cube first encountered in the Underdark by Uroq Mahwurld while the latter was temporarily separated from the Evening Group. Unlike other oozes and slimes, Glabbagool proved both sentient and non-hostile. He is not very smart by comparison to other sentients, but he is able to communicate via telepathy in a semblance of language.
Prior to meeting Uroq, Glabbagool claims to remember only a few weeks of time, the entirety of which was spent in the abandoned temple where Uroq met him. Presumably, the earliest point Glabbagool can remember is the point at which he somehow gained sentience. So far, no explanation has been forthcoming as to how or why that happened, but it may have something to do with the invasion of the Underdark by numerous demon lords. Specifically, the presence of Juiblex, the Faceless Lord, on the mortal plane may have somehow affected Glabbagool.
Since meeting Uroq, Glabbagool has accompanied him and his friends everywhere, in an attempt to learn more about the world around himself. When Alcyce was briefly summoned out of the Underdark to the village of Falling Rain in order to cast her Grow Plants spell and enhance the rice crop, Glabbagool chose to accompany her so that he could visit the surface for the first time. Sunlight proved to be emotionally overwhelming to him, and he was so entranced that he ceased moving and simply basked in the rays until Alcyce was ready to return.
No gelatinous cube is known to have visited the surface before, making Glabbagool unique in yet another way. It remains to be seen whether hours of absorbed sunlight will have any lasting affect on him.