"Alternate version of Simon from the opening of Tengen Toppa Gurren Lagann. Would have been the same as the post time-skip version, but rewrites made that impossible, so it's now a "bad ending" version. The name is a portmanteau of 'gar' meaning 'extremely manly', and Captain Harlock."
From Danbooru's wiki.
A rather small selection of images (26) ended up creating a rather decent adult Simon.