There are eight Adaptations in total that you can find in Another Crab's Treasure. Each is useful in its own way, and you'll want to collect them all to get the best possible loadout for Krill.

There are eight of these Adaptations in total, and you'll need all of them to earn the Well-Adapted achievement in Another Crab's Treasure. Here are all eight in order of worst to best, and where you can pick up these awesome powers.

There is an Urchin NPC that you can find in the Lower Crust in New Carcinia. The NPC is wearing a bottle cap and you have to exhaust his dialogue and encounter him a few times. It will deal you damage and he will eventually give you this Adaptation. I liked this one the least; it just seems to be flat damage and I found the staggers to be much more useful.

The Bobbit Trap is found in the Sands Between where there are a bunch of Bobbit enemies; it's just east of the giant trash can. This will allow you to plant a Bobbit in the sand that will attack your enemy and hold it if they walk over it. Level 2 deals DoT damage to the enemy it holds. Level 3 allows you to hold the enemy for a longer period of time. It's one of the least useful; you'll need to be able to predict how an enemy is going to come at you, but it can get you out of a jam.