The Diamond status ailment (referred to as "diamondized" in the game) appears solely in the game Earthbound, and functions similarly to the K.O. status. Whenever a hostile NPC "diamondizes" a party member,

Paula and Jeff with a diamondized Ness

they retain all of their HP and PP, but cannot attack in battle and follow the party around as a orange and gray diamond-shaped statue. However, they can be healed from this effect with items that normally restore a fainted party member (Cup of Lifenoodles, Horn of Life, Secret Herb). They could also be restored with the use of PSI Healing γ or Ω.

There are a multitude of enemies (and a few bosses) that can diamondize a party member, such as the Lesser Mook, Mook Senior, and the Evil Eye, all of which seldom use such an attack. The Diamond Dog and Trillionage Sprout can also diamondize a party member.