Daishain’s 5e D&D RPG Main Thread - Page 901 The Sage says...
Cratol and Poljen step up, striking out at their respective targets.
Then the naga says a word, and the entire room dims. Shadows grow, and twist, splitting off into shapes that begin to move about and harass the party.
Out of Character: Stopping there because this can have a major impact on people's plans. Essentially any targets more than 5' away from you have concealment now, in addition, people need to make Constitution saving throws at the beginning of each turn the spell remains active, success will halve the cold damage you'd otherwise take (12 for this round). Failure means taking full damage, and one's speed being cut by 50% for that round.
A DC 15 Arcana check will show the spell just cast to be of the Conjuration school. A DC 20 will reveal it to be an unusual spell, but one with some elements similar to that of Evard's Black Tentacles.
Initiative order: Poljen, Cratol, Naga, Poppo, Nikolaos, Lia, Zarra, Mari, Yuanti minions, Tazskan, Lawrance, Abominations, Velon
P.S. Anron asked about the foe closest to him. That would be a Yuanti pureblood. Essentially just a thin human man with small scattered scales and snake eyes. In spite of the name, they're at the bottom of the pecking order around here.