Spines are the result from detaching the purple quills found in two patches near the lodestone during the Tuska Comes event. Players may balance on them for Agility experience; balancing on a spine while there is lightning around it will grant the player ten times as much experience than balancing on the other spines. One spine in every patch will have lightning at one time. This is the same for every player and changes once about 35 seconds. Tuska fragments can also be obtained by doing this. The spines regrow into quills when the Tuska event is active.
After the Tuska Comes event ended, the spines could no longer be balanced on.
A player balancing on a spine