In Scottish folklore, the Kelpie will appear as a horse or a human in the water, and lure people to their demise! I would like to note that this particular Kelpie won't magically turn into a human while you're cuddling it. Or try to tempt you to a watery grave. Which is good.
Sit on a chair! Sit on a throne! Sit on this...toadstool? While a "stool" does sound like a comfy place to put your rear, in this particular case you would also be smooshing a cute little amphibian. So don't do that.