The copper egg adds 3 new stuff. You can find it from normal trial vaults and by using the trial key. When you get the egg and break it three random loot drops(1/3 drop chance for each). First we have infinite oxidized copper grate which you can use as an infinite block source. Second, we have a hardener wand that hardeners any block that you right click. The hardened blocks can be unhardened by right clicking on them with the wand or break them with tnt minecarts, end crystals or respawn anchors. The third and my favorite on is the copper solider that can be tamed by crafting the "Copper Control" which is a triangle made with 3 copper at bottom 2 on sides and redstone dust in middle and one copper on top or a copper nugget. The copper solider can be buffed by feeding it cut copper. Also you can give them swords and chests. Also if you craft the "Copper Wand" and craft 8 "copper flames" you can charge the wand by crouch+use and fill the wand with them you can select 8 soliders by using the wand on them and if you right click thewand normally the 8 flame soliders turn into a copper giant that deals more damage and has more health.
TheCopperEgg Team
