Yup! It's an actual MH product, be careful though even though their's parts to make two dolls in a starter kit; they only come with one torso to only make one doll, even though their should be two! But I believe Mattel's coming out with torso's for the Create-a-Monsters that didn't come with torso's or upper arms and thighs.
Yes, the sea monster does come with upper arms && thighs, the only Create-a-Monster's that don't come with upper arms && thighs are the add-on packs; the insect girl, three-eyed ghoul, && the skeleton. The ones that don't have matching torso's are the sea monster, dragon, skeleton, three-eyed ghoul, && insect.
The wigs that come with the Create-a-Monster's? Their...decent; you just have to force the wig onto the doll's head, but they work. Yeah, using a LIV wig may be a better choice.
It's going to be super hard mixing enough paints to match the orignal color of the sea monster's skin; but you could go and find a paint that closely matches the skin, better than spending 5 hours mixing paints. :I
Well, go shopping! Go on a monster high doll hunt! I know I last saw the Create-a-Monster Sea Monster pack at Target. Oh, && welcome back to the fandom!