Could be a zantedeschia (calla lily)

I was thinking of an arum lily [lords and ladies]but the leaf form just isn't quite right. though the middle bit does look like the beginning of a flower spike. pale green/cream cowl spathe with a purplish spadix in side.
if you didn't plant it do you like it? if you don't, dig it out sooner rather than later. I'd dig down really deep as I suspect there is a corm at the bottom of the stem.
if you are curious leave it and see what develops. if you do leave it let us know what it turns into please.

Please let us know!

I would say that SBG is correct. Perhaps because slugs and snails have been feeding on the leaves as they have emerged it has caused them to be deformed.

yes they do spread but I always leave a few at the back so that the berries develop and then they go on to feed the birds. then of course the uneaten ones germinate !