Incantation of Resurrection

Incantation of Resurrection (or the variant of) appears several times: The first variant appeared twice in episode 2 The second variant can be heard in the song Sucharaka San-nin Shuu.
 * 1) ちよた にけら はとほ らすて のはて きらと なりは してと
 * 2) ちよた にけら はとほ らすて ろ
 * Recited by Mai in stair-climbing game.
 * Later Mai tried to enter that phrase in her game - only to be notified it was invalid.

It's a reference to Dragon Quest 1, which in Japan used passwords rather than save games.