According to well-known Wii U data miner NWPlayer123, costumes for both Callie and Marie will soon be available in Super Mario Maker. A video posted by the user shows both costumes in action, complete with squid transformations and Splatoon sound effects. Callie and Marie will be released in amiibo form on July 8, so Nintendo might be planning to release the costumes around the same time as a promotion. For now, though, check out the video below: