Where do you live? Elephant ears (alocasia) are tropical plants and begin to deteriorate when temperatures decline much below 60F. Unless you live in southern Florida, it is much too early and too cold to leave these plants outside.

All you can do at this point is cut off the cold damaged stalk and hope the plant regenerates new growth from the bulb. Keep it warm and keep the potting soil moist, but not overly wet.

I live in zone 7 (Virginia). I have had the planter inside since planting the bulb until 2 days ago. Do you think it was the 40 degree temps for a few hours or the plastic cover that did it? When I took the plastic off, the soil was burning hot (steam coming out of the planter) and the stalk was limp (it was 70 degrees today). If I dig down far enough, the stalk is still solid inside the bulb and under the soil. Should I cut off the limp section? Also, the bulb seems to be peeling under the soil line (think artichoke). Is this normal? Thanks!

Sounds like it was cold-damaged and then steamed.

Uh oh, valuable gardening lesson in there: When you cover a plant with plastic, remove it before sunlight hits it.