Whispers of Madness

You whisper maddening thoughts into the mind of a creature you see in range who can hear you. The target must make an Intelligence save. On a failure, the target suffers a type of Short Term Madness for the spell's duration. You must use your action on subsequent turns to maintain the spell by whispering more maddening thoughts. Otherwise, the spell ends early at the end of your turn.

At Higher Levels. When cast using a slot of 3rd or higher, you can target an extra creature for each slot above 2nd.