Found in the Pig Fields, the Runt Pig belongs to the passive mob class, a mob class in which mobs have health and (sometimes) defense, but no method of attacks.

Their porkchops can be used in the iQTz (NPC) questline and in the Cooking Skill, and the Leather can be used to create armor at Delilah and Leather Handles at Hawn, which can be turned into the first post-tutorial non-crafted weaponry.