Of course they climb up walls :lol: They're just like any other urchin in that sense. They climb on rock, right? Rock = wall to them. They'll get suction on glass, acrylic, nylon, metal, etc.
first time hearing longspines as problems in the tank? what problems are they causing for you? I just want something that eats corraline... either it be a longspine or not. I just liked the longspines, they looked neat and spiky.
They're not evil or anything but they do grow fairly quickly, and before you know it you wind up with a creature that has a body the size of a silver dollar, with foot-long spines that knock stuff over / stab you / etc.