I've never heard them being referred to as 'elephant ears,' but I may just not be aware of that name. I looked up what the toxin is as well, and the main one is called gyromitrin (source: https://www.sciencedaily.com/terms/false_morel.htm#:~:text=False%20morels%20contain%20gyromitrin%2C%20a,and%20the%20central%20nervous%20system.)