Lihzahrdian Idol

Deep in the Jungle Temple (Temple Raider) sits the Lihzahrd Altar - use a Power Cell (temple chests, or lihzahrd drops) on it to wake Golem. He's the gentlest endgame boss: dodge the bouncing fists, unload on the head, step back when it detaches and flies. A roomy arena carved around the altar chamber removes most of the danger. His loot (Picksaw, sun-themed weapons) and the post-Golem world state make Tin-Foil Hatter and the Cultist next.