The Great Custard Flood of 99999.5 was the most devastating thing that has happen to Monstro City and plays a very big role in Moshi Monsters' history. It is was an event that only the eldest of Monsters will remember and Elder Furi, being the eldest Monster, will probably remember this.Not much is known about about the flood (apart from it being caused by Ryan Potter), but hopefully more information will be released.