When another face-up "Crystal Beast" monster you control is targeted for an attack: You can make this card the attack target instead. If this face-up card is destroyed while it is in a Monster Card Zone, you can place it face-up in your Spell & Trap Card Zone as a Continuous Spell Card, instead of sending it to the Graveyard.
These are the cards that are able to utilize the effects of a Crystal Beast being in the Spell/Trap zone as a Continuous Spell. Dweller in the Depths gain 300 ATK boost for every Continuous Spell card on your field, and Magna-Slash Dragon is able to send face-up Continous Spell card from your field to the graveyard, in order to destroy 1 Spell/Trap your opponent controls.
After your Amber Mammoth is send to the Spell/Trap zone, you can use Crystal Beacon to special summon Ruby Carbuncle from your deck to the field, in which Ruby Carbuncle’s effect allows you to Special summon as many Crystal Beasts as you can from your Spell/Trap zone back to Monster zone.