When I was a kid, we had a huge clump of elephant ears in the ell of our house. They were my "green playhouse" and once I sat out a rainstorm underneath them. I loved those elephant ears but was careful not to ever break a stem or tear a leaf. Mom said the juice was poisonous; I don't know if that's true but I was careful anyway.
The author mentions Colocasia spp in the footnote. Most times when people mention elephant ear, they mean a Colocasia spp. Sometimes Alocasia spp, and sometimes Xanthosoma spp.
While a very few of them are edible, all of the aroid elephant ears can be irritating to your skin if not outright caustic.
Eye-yi-yi, it's possible that you planted your "elephant ear" corm in soil that stayed damp too long. While most of these types like moisture, a wet spring can cause the corm to rot. Fast draining soil is the best for them. Plus a late season freeze could have killed the corm. Dig in around where you planted it, and see if anything is left. You might be able to lift it and replant in a pot to grow through early fall.