Dialga was a Legendary Pokémon of time. Not many trainers have ever said to see him which leads him to being a myth but you know he's real. You've seen him before but everyone acts like your joking or insane or very few believe you. Right now you were walking around in a cave until you heard something and saw Dialga show up.

Dialga: "Finally. A place without trainers to bother me. Time is all in order so no issues and everything seems in check. Wait I heard something."