Potato Masher
Duke Fishron
This happened to me while I was in a underground glowing mushroom biome. There were large towers of sand that were in my way, so dug it out using a normal Golden pickaxe. Not too long after starting to dig, I was suddenly given the Suspicious Looking Apple! Not sure if a worm managed to die somehow in the sand, but I had never saw or heard a worm entering the area.