"Mr. Sun" is, fittingly, the sun. He appears during the opening of each episode starting with the series premiere of The Lenny Leggo show. He will also make occasional background appearances during some episodes where the sky is visible during broad daylight.
Mr. Sun was deliberately drawn to be as creepy as possible to satire horrifying depictions of nature, such as Sunday School decorations. He was also given the most generic name as possible to satire generic television character names, such as the main bear family in "The Berenstein Bears".
Mr. Sun has no dialogue, nor does his appearance ever change in any way. However, characters will make occasional references to him, as well as shout insults to him from the Earth, such as on exceedingly hot summer days, to which there is never a reply.
Mr. Sun appeared in the background of the "Sky" logo, which was used as the show's official logo in 2016. While the logo was subsequently replaced with the "grid" logo for 2017, Mr. Sun, though he is no longer displayed in the logo, will still appear in the show periodically, just as he did before.
- Mr. Sun looked exactly the same 3,000 years ago as he does today.
- Mr. Sun was the first silent character to appear in the show. Theoretically, he is no longer the only, as The Innkeeper appeared in the Season 1 finale, The Worse Than Derek Savage Christmas Pageant, but had no dialogue.
- His character was created on February 29th 2016, the same day as Martin Anderson's birthday (although the drawing, recycled from an earlier, scrapped idea, was actually created about two months prior).
- Technically, "Mr. Sun" is both the heaviest and tallest character in the entire show. As the sun, his height is 864,948.7 miles and his weight is 1.989 × 10^30 kg respectively.
- Mr. Sun was the first character, of any categorization, to have been created that did not appear in this show's prototype incarnation "The Lenny Lego Show" at all.
- Before he was confirmed to become the true sun, "Mr. Sun" was originally created to be Lenny's coffee cup decor.