It’s the chair with the built-in blanket. The super ette Cocoon chair was desiged by Les M for maximum snuggling. I’m not sure if the thickness is more akin to a sleeping bag than a Snuggie, since I’ve never actually used a Snuggie (or at least I’m not willing to admit that I have) but it definitely looks pretty cozy. It doesn’t have the sleeves like a Snuggie though.
Rather than buy an expensive French chair that looks like you threw a Snuggie over it, maybe you could DIY this with a sleeping bag or Snuggie, some duct tape or velcro, and a chair. I’m posting this from my own homemade snuggle chair right now in fact.