I have stored my elephant ear in the garage the last 2 winters. This year it appears to be rotting. I can easily pull out one of the trunks and the top of each trunk has mold on it, and is very spongy. There are a couple shoots coming up, but do not look healthy.
Spongy and soft bulbs should be disposed of. They are not viable bulbs.
Temperature fluctuations are the likely cause.