Below is the thunderwings lion o prototype that appeared on thunderwings lion o cardback.
http://www.thundercatslair.org/forums/attachment.php?attachmentid=1316&stc=1&d=1373134107
http://www.thundercatslair.org/forums/attachment.php?attachmentid=1317&stc=1&d=1373134116
Looks cool! Is it a prototype or a repaint of the action figure? Either way, a very nice addition!
Definitely reminiscent of Mumm-Ra’s evil Lion-O disguise in the first-season finale “Fond Memories.”
Prototype
This is the thunderwings lion o that appeared on the cardback for lion o with thunderwings with red jump suit. Its arm and legs come off also and are held by pin.
Wow, what an amazing piece! I am extremely jealous.
is it worth grading it?
DO you believe is it worth getting this graded? Being 1 in the world a little nervous about shipping this item out :liono
INCREDIBLE!!! Many congrats on acquiring such an immensely rare item 
Wow, congratulations! That is a very rare piece indeed! Are his eyes painted too or made to look like the action figures? Take some more pics! Love seeing new prototypes!
How much for him.. You selling? 
Wow, missed this thread till WilyCub pointed it out.. Great find! Do you have some more pictures? Maybe some with the limbs off? Thanks!
Just chiming in as I would be thrilled to see more pictures also!
Whoa! That must be one of the rarest prototype in the thundercats toyline. Kudos on acquiring this gem!
That looks awesome and nice condition!
Amazing find! Frankly I wouldn’t get it graded. It’s a one of a kind, what would be the point? I would LOVE to see some more pics! Maybe a story with the Names redacted on how you got such an amazing piece!