Butterfly Is an event that took place on November 4, 2018 at 10:00 AM, PST. It was the Fourth "Live Event" in Fortnite: Battle Royale.
The Lead up to this event has been going on since the Blast Off event but was really set in motion by the Crack Closure event, when The Cube spawned. The Cube, also known as Kevin, would move around the map, and printed runes. The Cube ended its journey by rolling into Loot Lake, sinking into the lake.
At the start of Season 6 The Cube became active again, as it was revealed to be under the Largest island in the middle of Loot Lake, the island rose into the sky, creating the Floating Island. The Island started to move around the map, with the cube still attached. After another long saga of the cube moving around the map, it travelled back to the runes that it printed, and took their energy. Once all was said and done, the cube travelled back to Loot Lake now Leaky Lake. The Cube started to beam energy into the sky, creating a portal. This all culminated at the start of Fortnitemares when The Cube discharged a large amount of energy, destroying another Battle Bus and split open the island. After days of Fortnitemares, The Cube started to crack open, and leak energy into the lake.
After a day of leaking, the cube was finally empty. The Cube then started to spin, and emit white light, while turning grey, the cube finally exploded, and a blinding white light covered all the players' screens. Everyone was teleported to some sort of pocket dimension. After floating around for a while, a giant rift started to form. It took the shape of a giant Butterfly, multiplied, and started to shrink while moving over to the player. The players stuck out their fingers, and the butterflies landed on it. Then another flash of light appeared, and the players were back on the island, and coming down through a rift, with Leaky Lake now being covered by a new mess of islands.