Burn-to-join makes every new identity pay a toll before it may land. Joining requires destroying a non-refundable fee that floats upward whenever registrations spike, an island that grows expensive precisely when a crowd tries to storm it. A sybil farmer minting ten thousand puppets bids the price up against themselves, each clone costing more than the last, the burned fees piling into a cedar-strong deterrent. Honest newcomers arriving in quiet times pay no more than a pulse of pocket change. The attack funds its own defeat.