The stickysilk scuttlecrab replaced its ancestor, the marching scuttlecrab. The effectiveness at hunting of the stickysilk scuttlecrab is far and above much better than the marching scuttlecrab's. There is a single reason for this, and this is their evolution of stickysilk. The stickysilk scuttlecrab shoots its stickysilk out of its glands in its tail which is held over its body similar to a scorpion. This stickysilk has a sticky glob at the end, which when attached to something, is extremely hard to get off, while the rest of the silk remains unsticky. Their glands will pull back in this stickysilk, dragging their prey closer and closer.
The sheer power given by this stickysilk is the ability to catch things faster than itself, restrain prey, and haul around or out of the ground prey. They will work together to restrain a much larger prey such as a lizardworm, turning the tables on the once feared beasts. The greater of columns will catch and eat whole herds of other, larger creatures at times.
Their jaws are slightly stronger, and their ability to survive without food is slightly better. But, besides the stickysilk and scorpion-esque tails, they are behaviorally the same as their ancestors. However, it would seem that when some greater columns meet, they run into battle against each other, instead of merging and splitting off as before. Much smaller columns are also automatically absorbed into bigger ones.
This behavior, combined with their shear effectiveness, has driven them to spread over a vast distance from one side of Hydro to one side of Ittiz, consuming all in their path that isn't poisonous, though they remain not in rainforests or mountains, which remain safe from the stickysilk scuttlecrab scourge.
The columns stay aware from areas where the climate is currently bad, and also migrate from Hydro down, over to Ovi, to Ittiz, and then turn around.