If you set the date to December 21st, 2012 (or any calendar equivalent), a lot of meteorites, corruption (crimson in 1.2), a lot of hard bosses depending on the version (Skeletron in 1.0, Mechanical Bosses in 1.1, Planterae in 1.2, Duke Fishrons in 1.2.4, and MOON LORDS in 1.3), really infamous mobs (1.0 got DG's, 1.1 adds Clowns, 1.2 adds Ice Golems, 1.3 adds the Medusa, and 1.3.3 added Sand Elementals), hard events depending on update (Goblin Invasions/Blood Moons in 1.0, HARDMODE Blood Moon in 1.1, Solar Eclipses in 1.2, Frost Moons in 1.2.1, Pumpkin Moons in 1.2.2, Martians/Lunar Events/HARDMODE Goblins/PLANTERA Eclipses in 1.3, HARDMODE sandstorms in 1.3.3, and finally Tier 3 Old One's Army in 1.3.4), hackers (that look like Cyberchase's "Hacker" character while obtaining strongest equipments from Terraria's respective updates and having their own AI based on common hacks) and falling dynamites demolish the world while Tikopia plays, unused and rejected official items showcased by staff appear as very strong enemies, the False Messiah (like in Islam) appearing to make NPCs evil that they will taunt you by saying trashposts from the forum(as rulebreaking posts)/using Killaura to destroy you/homosexuality, and the sky turning red, thus killing the whole world and CRASHING THE GAME.