Blorbs

The Blorbs is a mysterious disease that appears in the events of Mario & Luigi: Bowser's Inside Story. This disease has spread all over the Mushroom Kingdom and infected the Toads. Fortunately, humans like Mario, Luigi, and Princess Peach are apparently immune to the disease. Those Toads that have the illness are taken aback as they grow large and round. It is caused by Blorb Mushrooms that Fawful sold to Toads, similar to how he sold the Vacuum Mushroom to Bowser. (The vacuum mushroom only makes your insides bigger, and gives you an extremely powerful vacuum breath.) The entire case of the Blorbs are wiped out by the Miracle Cure.

Trivia

 * Although the Blorbs are cured after Mario and Luigi use the power of the Miracle Cure, there is, humorously, one Toad that still has a Blorb-like condition in Toad Town, saying that it is what he normally looks like.