A DOLLAR-NEUTRAL RELATIVE-VALUE PAIR strategy on Binance USD-M perpetuals: simultaneously LONG ETHUSDT and SHORT BTCUSDT in equal dollar notional, triggered by extreme negative z-scores of the ETH/BTC ratio. CRITICAL DESIGN CHOICES driven DIRECTLY by the session's decisive failure pattern: (a) Long-only OHLCV breakout/momentum on alt-perps has DEFINITIVELY regime-decayed in 2025+ — 4 consecutive abandonments (BTC WRB, ADA Donchian, AVAX Keltner, LTC MACD). The analyst's explicit recommendation: 'REDIRECT new hypothesis generation toward mechanisms that worked through 2025-2026: shorter-timeframe mean reversion, options-based delta-neutral strategies, or cross-asset relative-value pairs — fundamentally different mechanisms that don't depend on directional follow-through.' This proposal implements that exact recommendation. (b) DOLLAR-NEUTRAL by construction — eliminates beta-to-crypto exposure that drove the failed momentum strategies into the regime-decay trap. The trade makes money on RELATIVE movement, not absolute direction. (c) MEAN-REVERSION on a STATIONARY SPREAD — unlike single-asset MR (which failed because absolute crypto prices are non-stationary trending), the ETH/BTC ratio has been historically stationary with strong mean-reversion characteristics across all regimes including 2025-2026 (ETH/BTC has oscillated in a ~0.04-0.08 range for years). (d) Uses ONLY the most liquid pair in crypto — ETH and BTC have the deepest order books, narrowest spreads, and most reliable execution. (e) MAXIMALLY SIMPLE — only 2 decision parameters (z-score lookback, entry threshold). (f) ZERO supplementary data dependency.