Bullet Time (Internal)

Until the spell ends, the target's speed is doubled

• If this is cast as an action, the next attack has advantage and the spell ends after the attack.
• If this is cast as a reaction, you gain advantage on Dexterity saving throws for the duration of the spell. 

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.