Devourer Of Universes

I was playing in a new world in 1.14 in a "galaxy" seed just for fun. I started to getting food and building an house for survive the first night. At night started to rain with a thunder and after 1 minute an inscription appeared in chat: "This is my world" and "I am the man of the space" I was shocked because I was in single player so I left the house and, in front of me, I saw a black-blue skin with an incredible blue eyes. He had in the main hand an enchanted trident and in the secondary a conduit. He tell me "I am the most powerful entity in the wirld" And "No one can do anything against me" After this he killed me with him trident and tell me "Go out or I will deleted you" I left the world and I deleted the world