Meta's Watermelon, the internal codename for Meta Superintelligence Labs' next frontier large language model after Muse Spark, faces an uncertain October 2026 release window amid ongoing training and limited official signals. Reports citing internal documents point to an October target, supported by claims from chief AI officer Alexandr Wang of GPT-5.5 parity on unnamed benchmarks using roughly 10× the compute of its predecessor, yet the July pre-training pause and subsequent resumption have shifted expectations to no earlier than that month. The absence of any launch or weights at the September 23 Meta Connect keynote, combined with Mark Zuckerberg's September 2 watermelon emoji tease, underscores the gap between internal milestones and public availability criteria that define market resolution. Traders weigh these dynamics against Meta's rapid iteration cadence and infrastructure spending, noting that verification of capabilities or further slippage could swing probabilities across the fragmented October dates.