Great Ape Kid Goku
Great Ape Raditz
The character falls asleep for a few seconds only, during which they are very vulnerable to attacks. If it is successful, the character's health and ki will recover, along with adding all stat bonuses.
Unlike most techniques, Sleep is part of most living beings (including humans, saiyans, and most alien races) natural body funcitions and as a result, it is one of the few techniques that can be used by anyone (even untrained persons like Bulma) regardless of power level.