Mud

2nd-level transmutation
Casting time: 1 action
Range: 60 feet
Target:
Components: V, S, M (a dollop of mud)
Duration: Concentration, up to 1 minute
Classes: Druid, Wizard
Subclasses:

The ground in a 20-foot radius centered on a point within range becomes thick, viscous mud. The area becomes difficult terrain for the duration. When a creature enters the affected area for the first time on a turn or starts its turn there, the creature must make a Strength saving throw. On a failed save, its movement speed is reduced to 0 until the start of its next turn.