I'm new to Terraria so I'm not sure if this is some sort of glitch. I was exploring an underground cave when I went to break a vase and a penguin popped up out of nowhere. I thought maybe I just hadn't seen it there as it was dark and partially under water but when I swung again another popped up. It only works when I swing the pickaxe, as I tried my other tools with no results. Is there something causing this that I'm missing or is it simply a glitch?