Crimson Bands

A Large or smaller creature of your choice that you can see within range is bound in bands of crimson red energy. The target must succeed on a Strength saving throw or fall prone, becoming incapacitated and unable to stand up for the duration.

At the end of each of its turns, and each time it takes damage, the target can make another Strength saving throw. The target has advantage on the saving throw if it's triggered by damage. On a success, the spell ends.