China’s Z.AI (Zhipu) confirmed it’s responsible for the viral - and mysterious - Ox Alpha AI model that swept to the top of online usage charts this weekend, pushing its shares up as much as 12% on Thursday. The Beijing-based company said it intends to price use of the model, now called GLM-5.3-Flash, at $0.15 per million input tokens and $0.50 per million output tokens, or units of artificial intelligence work.