Golem

The Golem is a boss and always drops 1 of the 8 items with 12.5% drop rate (Stynger + Stynger Bolts together).

It is found inside the underground Jungle Temple, which you can access after acquiring the key from killing the new hardmode boss Plantera.

Is summoned by taking Lihzahrd Power Cells to the Lihzahrd Altar

After killing this boss, Biome Keys should spawn [Needs Confirmation]