Texas Cactus (Peyote) . ("Lophophora williamsii.") Google search: "Lophophora is a genus of spineless, button-like cacti native to Texas from Presidio county south right along the Rio Grande River to Starr County, Texas. Lophophora williamsii or Peyote is a small, spineless cactus with psychoactive alkaloids, particularly mescaline. Wikipedia." (Pinned both to Nature - P&F-Succulents-*Odd Shapes/Appearances, N.O.C... & Texas Wildflowers....")
While growing peyote is not allowed unless you are a member of the Native American Church (NAC), it is a fascinating plant with attributes worth learning about. Read this article to learn more and find similar plants that you can grow.