If you control "Ancient City - Rainbow Ruins" and have its fourth effect enabled, use that effect to draw the stacked "Pegasus".
By using this card's effect on a monster equipped with "Crystal Release", you essentially shuffle that monster into your Deck in return for placing 1 "Crystal Beast" monster of your choice from your Deck into your Spell & Trap Zone.
If you activate "Counter Gem", use this card's effect before the End Phase to save one of the "Crystal Beast" Continuous Spell Cards.
This card can allow you to successfully use "Reversal Quiz".
Use this card's effect on itself to prevent you from Decking out.