What's awesome about this costume is, it's actually a fully functional Instagram camera. There is a mounted camera in the front, and the images taken are transmitted directly to the back panel and featured on an iPad.
What you need: You can replicate the idea, but it might be a little ambitious to include a camera in the costume. Make the "app" out of cardboard and printouts of the Instagram icon. See process here.
Don't forget to check out our 46 group DIY costumes!