My guess is thorny. I've read that at least some thornless blackberries are chimeras, with a thornless variety on the outside of the stems and a tasty but thorny variety in the tissue that makes the berries.
A large wild patch grows not far from my thornless patch. I don't know if the thornless self seeded or if it is a cross but a few years ago some odd ones showed up, canes and berries are larger than the wild or tame either one. Unfortunately they have the most awful thorns you ever what to see and growth is super aggressive. Shoots come up feet away from the main patch. I have kept them out of the regular thornless patch but they are overwhelming the old wild ones. The fruit is excellent but you can't get to it except on the edges cause the vines are so mean.
Nothing ruins a neighborhood like paved roads and water lines.