Twist Bioscience shares rose 22.64% to close at $142.39 on Wednesday after Anthropic named the company an independent evaluator for an AI-driven protein-design campaign. Anthropic used its Claude Opus 4.8 and Mythos Preview models to design proteins, which Twist produced at scale and tested for binding against 15 targets. The stock reached a new 52-week high, according to Benzinga Pro data, despite a critical report from activist short-seller Scorpion Capital. Scorpion called Twist’s AI drug-discovery narrative a speculative delusion, argued that Anthropic described Twist as an external evaluator and commodity contract research organization rather than a strategic AI partner, and said higher AI-designed protein success rates could reduce demand for physical constructs. Scorpion also criticized analyst interpretations and Twist’s use of a Regulation FD Form 8-K rather than a filing for a material definitive agreement, and disclosed a short position in TWST shares.