Let's see what wikipedia says.
They could be up to 2 meters long!
Only the earlier ones were marine, so most lived in brackish or fresh water. Which means we could frolic in rivers and ponds.
A eurypterid is the state fossil of New York! I wonder if they have been found in Washington, or Michigan.
Although many eurypterids had legs too tiny to do more than allow them to crawl over the sea bottom, a number of forms had large stout legs, and were clearly capable of terrestrial locomotion (like land crabs today)...Some species may have been amphibious, emerging onto land for at least part of their life cycle. They may have been capable of breathing both in water and in air.So we could frolic on land too!
They went extinct during the "Great Dying," i.e. the Permian-Triassic mass extinction, which as far as we know was the most drastic mass extinction that has ever happened on Earth, with up to 96 percent of marine species and 70 percent of terrestrial species dying, and needless to say many higher taxa being totally wiped out.
Other cool animals that bit the dust:
*Blastoids, which I have always liked. Well, "always" since I found out they existed. Warning: the image is huge for some reason.
*Trilobites (which were a whole class. Their extinction would be equivalent to all insects dying, or all crustaceans.)
*Acanthodians, and placoderms! I love placoderms. There is a cool on in the Ruthven natural history museum.
The Permian was a time of great diversity for insects and other invertebrates, and the largest insects ever to have lived existed during this era. The end-Permian is the only known mass extinction of insects.:(
Huh, somehow I didn't realize that it was that mass extinction which killed all those animals I liked off. Oh wait, that's because it DIDN'T. Other info says that the placoderms went extinct by the end of the Devonian. Tsk, Wikipedia.
But still, worst mass extinction ever, besides the one I'm living in :( It is my goal to one day write (more) about the Holocene mass extinction.
Okay, now I'm sad/mad.
But anyway, what should I name my imaginary pet Eurypterid? I like "Sherlock."