Those of you that are familiar with The Princess Bride (which should be all of you) know that Rodents of Unusual Size (aka ROUSes) are one of the largest dangers of the Fire Swamp (other than the fire and sandpits). But The Princess Bride is pure fantasy, right? Wrong.
ROUSes do in fact exist on an island of Gough. In actuality, they are house mice that have been introduced to the island, allowing them to be released from selective pressure on their size. And these mice are causing a huge problem: decimating bird populations by eating the chicks. So beware of the ROUSes while on Gough Island, because I imagine they would just as gladly attack you as a baby bird if you were to sit still for long enough.