So, the Sclerite Karka Shell...
Those are apparently Kraken tentacles and currently a cliffhanger. In the Solid Ocean Fractal, Jade Maw (a kraken) attacks using these tentacles. It’s scary and artistic in my opinion. This seems to have something to do with Mursaat, who had similar—albeit fuzzier—backs in GW1. The Sclerite back is amazing; I wear it to strike fear in my enemies hearts.
Tin Foil Hat Hearer »—> Ranger Extraordinaire »—> “Be like water…”