Yes. This is just flat out mean.
But its a thing. Although the degree to which its a thing is disputed.
But once its known these are a thing in your campaign, PC's in tropical waters won't be worried about crocodiles any more.
Candiru
by Cab Davidson
| Stat | Candiru |
| AC: | 8* |
| HD: | 1/8 (1hp) |
| Move (swimming): | 90' (30') |
| Attack: | 1bite + special |
| Damage: | 0 + special |
| No. Appearing: | 0 (2d10) |
| Save As: | NM |
| Morale: | 10 |
| Treasure Type: | Nil |
| Intelligence: | 0 |
| Alignment: | Neutral |
| XP Value: | 5 |
There are many species of candiru in fresh waters of tropical rivers, but only a few pose any risk. Those species are, when fully grown, a little over 2" long. They are essentially parasites, living on or in other fish in their river habitats, however they will try to infect any creature that they find in the water. They try to get into the urinary tracts of their targets, a difficult task that most fail to achieve. A successful candiru attack will typically cause it to attach to the targets skin, but 1 in 20 will find their target. The removal of a candiru from the skin can only be attempted by a character wearing gloves or gauntlets, or by one wielding an open flame, and inflicts 1 point of damage to the victim. But if a candiru has effectively found the urinary tract of its victim, the situation is far more serious. While no hit-point damage is inflicted, the victim is not quite the same thereafter. All natural healing is reduced by 1 point, and all magical healing by two. So, for example, a resting character always recovers one fewer hit point, and a cure light wounds spell would recover 1d6-1hp instead of 1d6+1. Every night that the victim has an undisturbed nights sleep, the cadiru is assumed to have parasitised one further hit point. Once the candiru has thus parasitised 10hp in total, it is ready to lay its eggs. The victim will at this stage suffer immense pain while passing urine, which will contain hundreds of eggs, and must make a saving throw vs. poison or become infected with a wasting disease and die within 1d6 days. If the subject survives, the cycle now begins again, but on each subsequent occasion when eggs are laid the victim suffers a -2 cumulative penalty to their saving throw.
A cure disease spell will remove a candiru, as will a cureall spell. Surgical removal is possible, but extremely damaging.