Scratch away the 14th door to find the Pond Blister.

The name refers to both the small, parasitic eels and their hosts. Attaches to a living body like a leech. At the end of an hour it can pump hundreds of larval spawn within the host, before shrivelling and dying. The unfortunate host becomes mindless within 4 days, bloated with spawn just under the surface of its skin, ready to burst. The host then seeks lakes and ponds to submerge itself and 'give birth'.