Some Taniana Elementary School 5th graders discovered this creature yesterday, attached to an intertidal rock in Jakalof Bay, near Seldovia. Judy, who spent much of the week volunteering to cook and chaperone the kids, took these pictures. The creature was attached to the rock with little suction cups on its underside.
It is, according to Judy, "about the size of a football":
Two commenters recognized it as a Lumpsucker. Well named critter, eh?
One thinks it is Cyclopterus lumpus. Another goes for Aptocyclus ventricosus (smooth Lumpsucker). I think it is probably the latter.
Thanks for the help, anonymous commenters!