As soon as I saw the clones, I knew they'd drop it. But I thought the "trick" was going to be that the clones could summon clones too (especially when it said they were "as strong" as the boss), so they would spawn exponentially, meaning 1024/etc clones for a near-"guaranteed" drop would be the solution.
It feels a bit goofy to have the MC panic over a 0.1% drop chance and then get it anyway after only having a ~7% total drop chance for it that quickly.