hammerhead shark+giant cuttlefish=my 'es un sharksquid'.
this is a design V1 for a hyperplushie I'm going to work on making (over five feet long/tall is what I use as a qualifier)
this design (though very simple, derp) is obviously not to scale.
I'm drawing it out as I go, and fixing it as I move along.

(1): eyepiece make 2 circular pieces and draw on or sew on eyes
(2): top head part, make 2 and sew on dotted line, leaving inner part loose.
(3):bottom of head and jaw, sew on/in mouth or draw it at this time- (flip it over) mouth should 'frown' rounded part up.
(4): main body is large and can be in two or four sections. four is best for maximum 3D effect and best tail alignment.
also draw or sew on gills at this time.
(5):tail and fin parts, sew at the side with fins up, curl the tail how you like it.
(6):fins, make 2 or 4 to your preference. attach to (4) as you see fit. (I attach behind the head)
(7): major tentacles- make 4. all about the same length or longer than (6) and curled as you like them.
(8):short tentacles, make 8 and curl as you like them.
(9):claspers/anal fins-optional attach as you like be it male or female. this is the female design.

feel free to ask about a better picture of the design, and link me if you make one!

edit: you can make this in any order and it will work, as well as seal on most seamlines as you see fit- also add fins and tentacles until you are happy with the number.
I can also post more shark headshapes and tentacle types, but those are all easy to imagine and create with a little work.