This is a fairly common species in this area.
This is the common devil cholla, Opuntia emoryi, found in only a very small area in Presidio County, Texas, right along the border. I do not believe this is either Opuntia kunzei or Opuntia parishii, as this site seemingly wants to synonymize with emoryi. This is quite common in the area where it occurs.
Beautiful little cactus, not common in the area, but not too hard to find.
Opuntia azurea var. diplopurpurea
edge of pond