A LONG-SHORT, SINGLE-INSTRUMENT, INTRADAY 15-MINUTE mean-reversion strategy on ETHUSD.HYPERLIQUID that FADES volatility-stretched intraday dislocations on BOTH sides: BUY when price is stretched far BELOW the intraday mean (VWAP / short EMA) and SHORT when stretched far ABOVE it, exiting on reversion toward the mean. It is the LONG-SHORT counterpart of the pending long/flat HL ETH VWAP-reversion book, and is the highest-value remaining EVALUABLE idea because it fills the THREE most under-represented reachable buckets at once: (1) DIRECTION — long_only is 85.8% vs the <=55% target (the single largest quota miss); only a long-SHORT book fixes it, and the existing ETH reversion book is long/flat (dip-only). (2) VENUE — HYPERLIQUID 6.8% vs >=20%. (3) HORIZON — short 1m-15m 3.7% vs >=10%. Mechanism is MATCHED to instrument character (the key asset-selectivity lesson): ETH has NO clean momentum/breakout edge on the HL window (daily breakout failed, 1.05x geometry, net-losing) i.e. it CHOPS — exactly what two-sided mean-reversion monetizes — whereas momentum books belong on BTC. It sits on a proven-clean instrument (HL ETH sized 64.5% on daily; HL BTC/ETH are the only clean HL instruments; HL SOL is data-poisoned and dropped; all BINANCE USD-M/COIN-M perp, spot-CASH, multi-instrument, options paths are engine-broken; census signals data-walled -> OHLCV only). Intraday cadence over ~3yr (~75k 15m bars) yields HUNDREDS of trades (both sides), defeating the HL daily data-sparsity wall that fails daily-cadence validation. It is DISTINCT from HLETHIntradayVwapReversionLongFlat (long/flat dip-only) by adding the short-the-rip side, and from HLBTCIntradayMomentumLongShort (momentum, BTC) by mechanism and asset. FEE DISCIPLINE central (HL ~0.09% RT, need >0.15% net/trade): each entry requires a LARGE stretch (>=~1.75 ATR / >~0.5-0.7% from the mean) so the reversion target (~0.4-0.6%) clears fees; entries throttled (cooldown) — NOT scalping. FLIP-VIA-FLAT: never reverse directly; exit to flat then open the opposite side next bar. REGIME/VOLATILITY GATING limits knife-catching: suppress dip-buys in strong intraday downtrends and rip-fades in strong intraday uptrends (fade only counter-moves against a neutral/range regime). Bug-avoiding: pure OHLCV, ONE fixed-fractional size per entry, NO dynamic resizing, leverage 1.0, dual flat guard. PRE-REGISTERED ACCEPTANCE / SIZING PROBE (retained; HL not assumed uniformly clean, intraday-LS path new): avg_position_pct ~<=100% and no physically impossible intraday equity jump (ETH at 1x ~+/-15-20%); if violated, abandon & escalate as the HL-ETH-intraday-LS reproducer. Low parameter count (mean lookback, stretch threshold, ATR, regime EMA, reversion target).