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.

More info on the Bulbapedia site