Not sure what type of calla lily it is, but it dropped a seed pod. Not sure what to do with it.
Calla Lily Seed Pod
Certified GKH Gardening Expert
If you're not saving seeds, you can simply cut it off or leave it. You can also choose to save the seeds by cutting off the dried seedpod and storing the seeds in an airtight container until ready to plant. Of course, seed grown plants will take longer to produce flowers. Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/bulbs/calla-lily/growing-calla-lilies-and-care-of-calla-lilies.htm