Snuggie is a popular brand of sleeved blanket. A sleeved blanket is a four-cornered blanket with sleeves, similar to a backwards bathrobe. It can be made of anything blankets are made of.

The answer to this question explains why a blanket does not normally need tzitzis. But the presence of sleeves raises some questions.

Is the presence of sleeves enough to constitute wearing it in the manner of clothing (derech levisha)?

Does the arrangement of the four corners not being on all four sides of the body still render it exempt even when sleeves are present?

(In a practical situation, CYLOR of course.)