Blocky saysProof of Stake secures a chain by having validators put up capital they can lose.
PoS (Ethereum since the Merge) replaces miners with validators who lock up (stake) tokens. The protocol selects them to propose/attest blocks; honest work earns rewards, while provable misbehavior gets their stake slashed. Security comes from skin-in-the-game capital, not energy — cutting power use ~99.9% versus PoW. The trade-off shifts to capital concentration concerns.
Power-ups you unlock
Validators stake capital instead of burning energy
Selected to propose/attest blocks
Misbehavior → stake slashed
~99.9% less energy than PoW
Double-Spend Dan attacks — common mistakes
Thinking PoS has no cost (capital is at risk)
Ignoring stake-centralization concerns
Assuming validators can cheat freely
Boss battleContrast what secures PoW (energy) vs PoS (capital).
Example code
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<body style="background:#06040d;color:#e6e0ff;font-family:monospace;padding:20px"><pre>PoW: burn electricity to add blocks
PoS: stake capital; cheat → slashed
both: cheating costs more than honesty</pre></body></html>