To complicate things, I have inspected agave (its length and girth) closely and I find it impossible to believe that it can hold within it such a fat and smooth thing. But I am no scientist.
I went to a village recently, which has agave growing left, right and centre. One woman suggested it could be Eetha Gadda, a palm, and my heart sank because its stump did look very fat. But then other villagers said it wasn't possible. They think it's most likely Agave and their ancestors probably ate in the past, during drought.
I plan to do a behind-the-scenes vlog for the article to explain what all I have tried and what all you may take further. For starters, a reader from the US says something similar from Agave is eaten in Mexico. A reader from Iraq says this may belong to a palm tree but the stump isn't as fat.
I hope you and botanists will tell me more.
Good luck.