Meta's internal documents and executive updates have positioned the Watermelon frontier large language model as the successor to Muse Spark, with a targeted October 2026 launch window following a July pre-training pause. Chief AI officer Alexandr Wang reported in a July town hall that the still-training model, using roughly 10 times the compute of its predecessor, reached parity with OpenAI's GPT-5.5 on unnamed internal benchmarks, though no external evaluations or model card exist. Mark Zuckerberg publicly teased the "significantly more advanced pre-train" as coming soon in early September, yet Meta Connect passed without a release. Traders are monitoring Meta's infrastructure buildout, Muse integration plans, and any October announcements against OpenAI's rapid GPT iteration cadence, with resolution hinging on verifiable public availability or weights.