god mode

Short definition from Wiktionary

Noun

1. 1
   A game mode where the player character is invulnerable to damage, typically activated by entering a cheat code.
2. 2
   A mode of play in (mostly) roguelike games, allowing the player to create objects on demand, to be resurrected in the case of death, etc.
3. 3
   A temporary state of extreme skill (in a sport, video game, etc.).