Opuntia, commonly called prickly pear, is a genus in the cactus family, Cactaceae. Prickly pears are also known as tuna, sabra, nopal from the Nahuatl word nōpalli for the pads, or nestle, from the Nahuatl word nōchtli for the fruit; or paddle cactus.
Once your Opuntia has roots, care is very simple. A pot with adequate drainage can help prevent this problem. You wouldn't want someone to force you to drink when you're not thirsty, and these prickly pears are the same.