The seatick crastrum has replaced its ancestor the spearhead crastrum and spread further to the Yokto coast. Its one large spike has become hollow and is used to the pierce the skin of its prey and 'suck' its blood. They will sit on rocks and absorb sunlight for the majority of their lives but, if they sense a large presence of another organism passing by they will force themselves from their perch and shoot quickly towards the vibrations. Once there they will get even more energy by absorbing the blood and will also be placed in another location after they drop off their host spreading their range even further. They have also developed a primitive digestive system. There is a sac like structure under their spike where the blood will drain into. Once there the nutrients are absorbed. Once all the nutrients have been absorbed the sac will contract forcing the waste of the blood back out of the spike into the water. This sometimes attracts predatory animals near the seatick crastrum allowing them to quickly get another host.