There is a mystery item in my inventory that I picked up from the nether

I was in the nether with a looting 3 sword and I killed a few endermen in the warped section of the nether. I realized that in my inventory there was a zoomed in spawn egg that when I held I couldn’t see it. I then somehow got 3 more and now currently have 4. I split one from the 4 and dropped it from the menu and it was invisible on the ground but I picked it up. I also can’t use the button to drop it from my hand. I saved and quit and it is still there, so I have a mystery item that only says it’s from the nature category.