Triple Time

Choose a willing creature that you can see within range. For one round, you compress time for that creature.

On its next turn, the target creature gains a +2 bonus to AC, has advantage on Dexterity saving throws and all contested Ability Checks, cannot be targeted for opportunity attacks, and can take three full turns instead of one. Because time is compressed for the target creature, however, it may cast only spells targeting itself; all other spells expend a spell slot but fail automatically.

When the spell ends, the target can't move or take actions until after its next turn, as a wave of lethargy sweeps over it.