A market-neutral, two-leg statistical-arbitrage pairs strategy on Hyperliquid perpetuals: trade the ETHUSD/BTCUSD price ratio when it dislocates from its rolling mean, holding a beta-balanced long-short pair so net crypto-beta is ~zero. ETH and BTC are the two most correlated crypto majors, so their price RATIO is far more stationary than either leg alone — relative dislocations (driven by rotation flows, ETH-specific catalysts, or transient liquidity imbalances) tend to revert because both assets share the same macro beta. This deliberately AVOIDS every active failure mode in the recent log: it is NOT a single-name directional/reversion bet (ETH single-name on HL has failed momentum, breakout, AND VWAP-reversion — this trades the residual ratio, not ETH's direction); NOT funding-as-signal (the entire funding-directional family is a graveyard — this uses OHLCV only); NOT supplementary-data-gated (no OI/liquidations/options-IV, which only cover a ~1-month recent sliver and render strategies untestable); NOT options (dodges the ~0-capital options sizing bug); and NOT CASH-spot (perps on a MARGIN venue, dodging the multi-instrument cash-overfill engine defect). It fills three under-represented quota buckets simultaneously: HYPERLIQUID (7.6%->target 20%), pairs scope, and long-short/market-neutral (14%->more headroom). Only 3 core parameters (z-window, entry-z, exit-z) to resist the overfitting that has recurred this session.