The last outfit is behind a gate that opens when you stand on a plate. The problem is there are boulders rolling down the stairs and across the plate that you have to keep avoiding. No matter how I've tried, I can't get from the plate to the open gate before it closes. I've tried coop with the wisp but he can't activate the plate or open the chest. I've tried charged air and ice arrows at the boulders to try to slow them down or even stop them. I assume it's the outfit that is in this chest I suppose it could be coins and that I totally missed it somewhere else. HELP!