Discussion: Cholla?

I have never heard of this fun-sounding object. Enlighten me. (What's a cholla?)

Cholla catus, aka "Jumping cactus", for its propensity to attach to anything which even lightly brushes against it. When you brush one or two spines, the entire pad (which ranges from mouse-size to orange-size) breaks off from the plant and remains attached to you. Those new to the desert who then try to grab the offending pad and try to pull it off immediately regret that decision. Best way to remove one is to grip the pad between your compass and a rock (don't pick up any scorpions with the rock!). Some desert regulars carry combs which can also be used to flick them off.

A common cholla attack involves stepping on one of the pads which has dropped from the plant. With the next stride, the pad, now stuck to the bottom of your shoe, brushes the calf of your other leg, to which the cholla then attaches itself.