Ebongrass

Grass or weeds that have been affected by The Corruption. What used to be normal grass is now a dark grayish purple and bearing sharp spikes as long as a human finger, ebongrass randomly produces ebonthorn from any of the seed-bearing grass in its patch.
A sample of ebonsand was brought to the unnamed robot's Sphere, and it was left with its other supplies on top of a Grass Block. One of the Grass Blocks was converted to an Ebongrass Block, which spread from there.