Actions

Crucio

From Hayashi Park Potterverse for 5th ed. Dungeons and Dragons (5e)

Crucio

4th-level evocation

Casting time
 1 action
Range
 60 feet
Components
 V,S
Duration
 instantaneous
Process 
The spell inflicts pain upon the target creature. The creature takes 1d8 + spell modifier points of psychic damage for 4 turns, the target creature makes a Wisdom saving throw each turn to reduce the damage in half. If reduced to 0 hit points, the creature is unconscious but stable. The target can be awoken the next turn.[1]
At higher levels 
A higher level spell slot can be used instead and when using a 5th level or higher, the damage occurs additional turns for each spell slot level above 4th.[2]

Harry Potter Spell Description

Inflicts intense pain on the recipient of the curse; the pain is described as having hot knives being driven into the victim. It cannot be cast successfully by a person who is doing so out of pure spite or anger; one must feel a true desire to cause the victim pain. If one casts this spell, he or she will receive a life sentence in Azkaban prison for it, as with the other two Unforgivable Curses.[3]

Etymology
 Latin crucio means “I torture”.