There is something to be said for the phrase "learn something new every day." Even I, in all my wormly knowledge, did not know about these:
They are called nemertean worms, and are a whole phylum of carnivorous worm awesomeness. I only had the faintest knowledge of their existence (i.e. "huh, nice worm, wonder what it is?") before finally getting their name on a BBC broadcast in Best Buy. They fascinated me, moving swiftly towards the seal corpse alongside starfish and various other eager feeders. The last time I had seen worms like that was in a 'pseudo-pond' in micro-bio!
Nemertean worms are very diverse. Worms like the seal-eaters above can be found in both fresh and salt water with one lucky species found on land in Java. They can range anywhere from a few millimeters long to 100+ feet, making these worms the longest animals alive.
Nemerteans have interesting anatomy. They have probosces that may or may not be armed with a sheath with which they probe their prey. These worms are thus classified based on whether their probosces are 'armed' with solid piercing materials or not. The ones with sharp points on their probosces can also be toxic. Said toxin is under examination as a possible means of memory enhancement.
As with many worms, nemerteans have amazing regenerative capabilities. Cut off a piece of one of the larger ones and it becomes a whole new worm. They can also reproduce sexually (with or without hermaphroditism). Even the most durable vertebrate looks fragile as glass by comparison to these guys.
It feels like a single entry does not do these worms justice. They are so cool, but I only just learned about them. It's hard to sandwich the awesomeness of ribbony, velvety carnivorous worms into an entry like I would with a single species.