Without using commands, installing a mod, or abusing a bug (for example, it used to be possible to place a dirt block under a bedrock block, till the dirt block with a hoe to create farmland, and plant wheat in the farmland, which would overwrite the bedrock block with wheat), it is impossible to break bedrock in survival mode. Some versions of this lie assume that bedrock can be mined, but it takes many hours, which is not true because, in the code, bedrock has a hardness of -1, which makes it impossible to mine. Also, bedrock has a blast resistance of 18,000,000, so an explosion powerful enough to blow it up is more than enough to crash the game.
There is a way to ride or tame the Ender Dragon.
It is impossible to blow up obsidian.
Obsidian has a high but finite blast resistance (6000). It is possible to generate an explosion powerful enough to destroy it, but only through mods or commands. However, blue wither skulls are a special exception - their explosion treats most blocks (except the ones that are supposed to be indestructible, like bedrock) as having a blast resistance of no more than 4, meaning they will blow up obsidian with ease.
You can get to the Nether/End by mining through bedrock.
Even if the player somehow mined through bedrock, all they would encounter is a bottomless pit, known as the void. After falling below the Y-coordinate of -64, players start to take constant damage. All the player would accomplish by mining through bedrock is dying and losing all carried items.
You can craft emerald tools.
There are no emerald tools in the game data. They can only be added to the game by installing a mod.
You can destroy the world by pressing the T button.
There is a mysterious entity in Minecraft known as Herobrine. It looks like the default player character ("Steve?"), only with white eyes. It haunts players' worlds and acts similar to a human, even if the player isn't connected to a server of any kind. Herobrine tends to move objects around, gaslighting the player. He also likes to appear behind the player and attack before disappearing. Legend has it that Herobrine is the spirit of Notch's deceased brother, haunting Minecraft and its players.
There is no such thing as Herobine. All occurrences of Herobrine are made through mods or texture edits.
There is a secret "Hieroglyph" item in Minecraft.
Creepers are attracted to Glowstone and will destroy glowstone structures.
If you gather the Heads of each Mojang employee who worked on Minecraft and gather them in a circle, Notch will appear and grant the player one wish from a list of 110 possible wishes.