The Blue Ones
From Homestar Runner Wiki
The blue ones are most likely Strong Sad's favorite underwear. When Strong Bad told Strong Sad that all his underwear had somehow ended up individually priced and labeled on an online auction site, it was this pair that he tried the hardest to retrieve. It takes him a while (apparently 24 hours, since Strong Bad managed to watch the entire Caleb Rentpayer marathon), but Strong Sad eventually manages to find his favorite underdrawers at the end of the cartoon. He proclaims that "The world is saved! I found the blue ones!"
Strong Sad's love for The Blue Ones seems odd because in his Lament, it's stated that he doesn't wear clothes.
- Debut: Bug In Mouth Disease