I found this outside on my deck …
Is it slimy? Like seaweed?
Actually it appears to be dried out.
Closeup of underside:
It’s beautiful…Is it a dried piece of kelp or seaweed ? Would make a great B/W photo 
That’s really neat! Looks more like a star fish of some sort.
Looks like a mutated starfish.
Flying starfish Batman … I’m at least 1/2K from the ocean!
I am pretty sure it’s a sea creature. The hole in the middle makes me think it’s a star fish of some sort. Star fish eat with a hole in the centre of their bodies. It’s actually their stomach. They turn it inside out and eat up their prey. Maybe a dog or cat brought it to your porch. Or a raven or seagull. Regardless, it’s pretty cool! When my ex- fisherman husband wakes up, I’ll ask him what he thinks it is.
As Princess of Power mentioned, I do believe a dog brought it to your house. I know whenever my dog gets loose (doesnt happen often) she brings the wierdest shit home.
Looks like a piece of corral, most likely dropped by a bird…or a tornado
More likely a basket star or feather star rather than a sea star.
Hey Soggy, you willing to donate that creature to science?
That is an interesting piece of work, I would put something on it to preserve it and hang it in the garden or out on the highway sign to scare tourist away.
To science it is …
Mig, let us know what Peter says it is.
Yeah, that does look like some type of sea creature, starfish. Very cool. 
That is exactly what it is. It is an echinoderm of the class Ophiuroidea which contains brittle stars and basket stars.
THE WINNNNNNNAR … BIG THUMB!
And thanks for the ID.
My guess would have been Republican.
What ever it is…that is pretty neat. 
I and some other people say that we are indeed aliens. All different races of people are from different planets.