Shiny Mantle
Unique Mage Armor, 10 gold. Backpack Battles item.
Shop entered: Consume Star items and generate random Gemstones. Every 5.5s: Use 3 Mana to become invulnerable for 1s + 0.2s for each 10 GoldCoin worth of Gemstones you have (up to 3 times). Increase Mana cost by 3. On invulnerable: Inflict 3 Blind.