A concept called mystery bag in expert mode when you defeat a boss there is a chance you get this what it does it gives you a random treasure of any boss
I got this dev stuff from opening golem treasure bags : r/Terraria
Steam Workshop::Better Treasure Bag Loot
Terraria 1.3 Expert Mode Treasure Bags | Top 5 Best Expert Mode Items | PC | XBOX1 | PS4 - YouTube
テラリア – Eye of Cthulhu討伐 | ウチゴハン
Terraria 1.3 Expert Mode ALL Treasure Bags - ALL Expert Mode Items / XBOX ONE!!! - YouTube
r/Terraria on Twitter: "[Calamity] Farmed the Devourer of Gods for almost 2 hours trying to get the rare drops (2.5% each). Didn't realize you could just get them from the treasure bag
Menacing treasure bag” +4% damage : r/Terraria
Co wiesz o grze Terraria. | sameQuizy
r/Terraria on Twitter: "Girls, girls, one at a time. https://t.co/4BZpC6ofr7 https://t.co/UUpBtVmjSB" / Twitter
Farming some treasure bags....I need some yoyos. : r/Terraria
Treasure Bag (Slayer God) | Terraria Spectra Mod Wiki | Fandom