A pair of favourites. the Crab and King Crab!
Melee units were always the hardest to design for a sci-fi setting, and falling back on creature designs always gave me a good base to start with. The original sketches for the Crab were done while in vacation in Hawaii, which was also a possible influence?
I also really loved working with this faction's color scheme and designing their logos.
Final models for both crabs by Chadwick Dusenberry
https://www.artstation.com/artwork/zxPY3w
https://www.artstation.com/artwork/oJXAJk
And Kevin Spangler did a great job bringing these to life
https://www.artstation.com/artwork/EzKGk0