Frogspawn

Frogspawn is a deadly disease which occurs as a result of the strange reproductive properties of certain types of black toads found on the Magnian Peninsula, near swamps and marshes. These toads carry their eggs like seeds on their back, which appear as dots on their skin. However, these eggs consistently drizzle off the toad's back, allowing it to be deposited in organic material, such as warm flesh. The eggs slowly burrow their way beneath the skin of their vessel, causing increasingly painful rashes and itching. 
Here, the toads will grow to full maturity and erupt from inside the body after about a day, more often than not killing their vessel in the process. It takes only a few hours for a new-born toad before it becomes fertile and can produced its own batch of eggs.