Flopside

Flopside is the complete opposite of Flipside from the game Super Paper Mario. It is accessible after Chapter 4. As a complete reverse, even the people are in the reversed place, with reversed personalities. For example, Pook of Flipside loves the sea, while his Flopside counterpart, Puck, prefers the sky. They are both located in the third floor of their respective towns. It has the same places from Flipside in reverse direction, even including the Pit of 100 Trials. One of the salesmen is called Flamm, a counterpart to Flimm.

More importantly, Flopside's Heart Pillars are all located in the same place as Flipside's. Also, Saffron's counterpart mixes two items instead of simply cooking one.

If Mario flips to 3-D on the second floor of Flopside, he can pay 300 coins to have a warp pipe constructed by Merlee's house that connects to a warp pipe by Merluvlee's house. This creates an easier route between Flipside and Flopside.

Creation
When the Tribe of Ancients created Flipside, they realized that without darkness (as Flipside was a "light" place), Flipside would fall into ruin, as light cannot exist without darkness. In response to this, the Tribe (along with the Tribe of Darkness) created an antithesis to Flipside: Flopside. To this day, Flipside and Flopside still mirror (and secure the peace of) their respective counterparts.

Trivia

 * Though many assume only a select few in Flopside know of Flipside, by the time the player has beaten the game many residents will mention Flipside--one of them in fact moves to Flipside.
 * Flopside's name derives from the second half of flip-flop, flop (as opposed to Flipside deriving from flip).