>>536373752
It's because they don't go up to her shoulders like other octopus characters, because this is a game where you're mainly seeing the character's back. This is also likely why seed sr.'s skirt is very plain; you won't often see it in normal gameplay.
One thing I can't quite tell is whether or not the tentacles are hand-animated or if they're just using hair physics. I'd like to think they hand-animated it, but the fact that they don't interact with anything she's doing makes me lean towards hair.