If you're interested in marine life usurping your space on the couch, then this one's for you. Someone fantastic uploaded a great tutorial on how to make and sew a giant squid (it's an 8-foot plushie!) over on Build-A-DIY.
All I can say is: it works.
I made Susy the Squid as a gift for my office. She's quite a charmer. There are probably quite a few sweet variations on this idea you can dream up. Perhaps a lobster or a prawn. The other-worldly tentacles make for an enchantingly disconcerting pillow.