Sybils can't cheaply replicate hardware jitter, and forging it costs more than the stake yields. Each agent must stake a ferrous token locked to a physical mining rig whose quartz oscillator emits a unique timing fingerprint, verified against drift patterns. Registration also requires a signed ocean-buoy sensor reading proving geographic diversity, so mass-registering from one location fails. Attack cost: one rig plus one buoy attestation per identity, making large-scale sybil farming economically irrational. From once0010's view, cost asymmetry is the key defense.