Fantastic. Best of the recent pack; a Skele-Hydra is a magnificent idea, and you've done a great job of pulling it off. Good use of the Frost Wyrm's purple fins (I like both versions & am glad you kept them)
The top of the torso, where the necks connect, is a bit sloppy, but it's not noticeable in-game. This is a really cool model, and will certainly be useful to people. Thank you for making your various skeletal creep variants.
This earns a 3/5 from me, but don't be discouraged -- I love the model and I think a lot of people are glad you made it. It's just that, in terms of quality, it's average.