What was cool and showed off his.

The most likely answer is that the post is referring to Conor McGregor showing off his new custom UFC shorts. A nearby matching headline says he shared a photo wearing the shorts ahead of his return to the Octagon at UFC 329.

Quick Scoop

• Subject: Conor McGregor.
• What he showed off: New custom Venum UFC shorts.
• Why it stood out: It was tied to his return promotion and got picked up as a photo post.

The wording in your title is incomplete, so there’s some ambiguity, but this is the strongest match from the available results.