Terraria: Boss Summoning Items & Crafting Them
Summoning Item: Mechanical Eye Materials to Craft Mechanical Eye: Lenx x3 - Kill Demon/Wandering Eyes outside at night. Soul of Light x6 - Kill Underground Hallow enemies. Iron/Lead Bar x5; Notes: Craft at Mythril/Orichalcum Anvil. Before the defeat of it may be dropped by any enemy randomly at a very low chance. May also spawn randomly until then.