The top-tier subscription unlocks access to xAI’s best-performing model, Grok 4 Heavy, and special settings for interacting with two custom characters designed for flirting or chatting. You can turn on an option called “bad Rudi,” which immediately transforms the character into a foul-mouthed chatbot that slings insults only a high schooler could find funny. After I said hello, bad Rudi replied, “Hey, do Bucha? “I'll skull fuck your dumb ass brain with a beer bottle instead, you miserable prick,” bad Rudi continued. The latest Grok model prompted a lot of chatter in the AI community.