The Harmony Scarves (Japanese: きずなのスカーフ Scarf of Bonding) are a pair of scarves in Pokémon Super Mystery Dungeon created by Mew, an ancient Pokémon, long before the events of the game. They were made from material of the Tree of Life as a countermeasure to the powers of Dark Matter, and wearers are granted its power when close to the Tree of Life.
The Harmony Scarves are first introduced after saving Budew at Nectar Meadow when the player's partner gives one to the player as a sign of friendship. The partner reveals that the scarves had been found by his foster father Carracosta, who had found the partner wrapped up in the two scarves. It is later revealed that the Harmony Scarves had been handed down for generations until they had been found wrapped around the partner.
The scarves first activate at Fire Island Volcano, which induce the player and partner to evolve into their final forms, allowing them to defeat Entei. The player and partner then devolve back to their initial forms after the battle.
They next activate outside the Tree of Life when the player and the team meet Nuzleaf, two Beheeyem, and Yveltal, who attempt to petrify the player and their team. However, the scarves protect them from being turned to stone, and again allow the player and partner to evolve, helping them to defeat the four Pokémon. The evolution is undone when Dark Matter pulls the Tree of Life off the ground. The Harmony Scarves activate a final time while the player and partner are teleported into the Tree of Life by Arceus, allowing them to evolve and resist the power of Dark Matter, who would petrify any other Pokémon inside the tree. The scarves also help them breathe easily in the thin stratosphere while inside the tree. The player and partner stay in their evolved forms until the first battle against Dark Matter is over.
In the epilogue, Ampharos helps restore the player's partner into the world by using the power of the player's Harmony Scarf. During Ampharos's plan, the player is lead to the bottom of Purifying Cave, where their scarf begins to glow as a strong response for their wish not to lose Mew (a different Mew from the creator of the scarves) and combines with the light surrounding Mew. The player's Harmony Scarf then disappears and their partner is restored from within Mew, with their scarf also gone.