Hypnokinesis (from the Greek word hypnos, meaning sleep) is the ability to manipulate sleep patterns and, by extension, dreams. This can be used to induce instantaneous sleep on biotic subjects, or to induce perpetual insomnia (which in a few days can kill you). One with this ability can remove the need to sleep from any biotic subject, or make them dreadfully tired all the time. One can also cause the subject to sleep forever in a comatose-like state and can even determine how deep a sleep or how long a person or people has. This has been seen to be very powerful, as proven in The Last Olympian. Hypnokinesis is primarily used by Hypnos and his children, though, as shown in The Blood of Olympus demigod children of Hades are shown to possess this power as well.
About two months before the start of the book, Grover Underwood while in Central Park sees Morpheus walking around and puts Grover to sleep for two months before Percy Jackson and Nico di Angelo wake him up. Later, right before the Battle of Manhattan, Morpheus places a huge sleeping spell over the entire island of Manhattan causing everyone, but the demigods, gods, Titans, monsters, and clear-sighted mortals, to fall asleep.
When Annabeth Chase and Jason Grace walk into Hypnos' cabin to get help from Clovis, Jason Grace finds himself falling asleep and Annabeth warns that if he falls asleep inside the cabin, he may never wake up.
After Shadow Traveling to a small ship outside Camp Half-Blood’s shores, Nico puts the mortals aboard to sleep.
The general abilities of Hypnokinesis include:
- The ability to put people to sleep.
- Astral projection/dream travel, as in The Lost Hero, Clovis, son of Hypnos, says to have met Michael Jackson in his dreams. In The Blood of Olympus, Nico astral projects himself into Clovis' dream, in order to send a message to Thalia. Hence, demigod children of Hypnos and Hades have much higher control over their dreams than other demigods.
- May be able to manipulate dreams, since dreams are a part of sleep.
- Can recover lost memories.
- Hecate (limited, with a sleep spell)
- Persephone (limited, via Stygian sleep)
- Lupa (limited)
- Apollo (limited)
- Hypnos' Cabin members
- Nico di Angelo
- Hecate's Cabin members (limited, with a sleep spell)