Power Word Stun
You overwhelm the mind of one creature you can see within range. If the target has 150 Hit Points or fewer, it has the Stunned condition. Otherwise, its Speed is 0 until the start of your next turn.
The Stunned target makes a Constitution saving throw at the end of each of its turns, ending the condition on itself on a success.
Power Word Stun 5e 2024 vs. 2014 edition differences
The 2024 version replaces the "no effect" clause with inflicting the Stunned condition directly, and grants the stunned target its Speed to 0 until the start of your next turn if above 150 HP. It also clarifies the saving throw ends the Stunned condition on a success, rather than ending a separate effect.