PSI

PSI (Psionics), including the subcategory PK (Psychokinesis), are the psychic powers that appear throughout series.

Origin and discovery
PSI was originally the provenance of Giygas's race. When George and Maria were abducted by these aliens in the early 1900s, George studied the powers and eventually passed down his research notes to Ninten, his great-grandson. Many humans with no connection to the aliens or to George's family line are also shown to be able to use PSI, such as Ana, Ness, Paula, Poo, Lucas, Claus, Kumatora, and the Garrickson baby.

Types of PSI
PSI moves become stronger as the user levels up, with the level of strength denoted by the Greek letters α (alpha), β (beta), γ (gamma), π (pi), Σ (sigma), and Ω (omega), in ascending order of potency. The π power level only appears in , while the Σ power level is not used outside of Earthbound. PSI can be compartmentalized into four different categories:
 * Assist PSI: for PSI moves that alter parameters of allies or foes, inflict status effects, or raise shields.
 * Offense PSI: for PSI moves that inflict damage. All PSI moves in this category bear the prefix "PK", except in Earthbound, where "PSI" is used instead.
 * Recover PSI: for PSI moves that replenish HP or PP, or remove status effects.
 * Other PSI: for PSI moves designed to be used outside of battle on the field map, such as Teleport. No PSI of this category exist in Mother 3.

Qualities of PSI
PSI costs PP to use, which can be recovered by eating certain foods or resting at a hotel. When a character can't concentrate or is forgetful, they can't use PSI. In Mother 3, when a character is learning a new PSI technique, they will become feverish, slowing them to a walk.

Memo
"PSI is a mysterious and useful power that can replenish your energy or even assist in your transportation needs. Using PSI will deplete your PP."