Pontius the Protip Potato is a non-existent (right now) npc, created by setk. Many people have agreed that an npc that gives rules and/or protips is needed. And why not have a potato npc? ;P
Despite not existing, (like block trolls) Pontius the Protip Potato has been referenced before, and might one day exist (also like block trolls).
Quick Backstory: Pontius was a wayward king who was turned into a potato for eternity, for his misdeeds. He is now trying to redeem himself by helping people, and giving protips.