Like a one-person hot pot: the vegetables, tofu, meat and noodles you choose are cooked in a spicy, numbing beef-tallow broth and served in it, often with rice. Shops offer milder and hotter levels.
冒菜 is often called 'one-person hot pot'. It originated in Chengdu: the vendor boils (冒) your chosen ingredients in a spicy broth, then serves them in a bowl with ladled soup. Compare 串串香 (on skewers) and 麻辣烫 (similar dish, more common outside Sichuan).