Mass Polymorph

[ Métamorphose de groupe ]
level 9 - transmutation
Casting Time: 1 action
Range: 120 feet
Components: V, S, M (a caterpillar cocoon)
Duration: Concentration, up to 1 hour

Description not available (not OGL).
But here is a summary:

Transform up to 10 creatures into new beast forms whose CR or level are equal to or less than the creature's CR or level.
Bard
Sorcerer
Wizard
Xanathar´s Guide to Everything
  1. DnD 5e Spells › Mass Polymorph