I dropped a villainous skull down on the sloop in front of the door of the brig, right in that little corner on your left as you hit the bottom of the stairs. It was stuck clipping inside the bar. Not in the brig but not out of it either. I was sure I could pick it up but I was wrong. Eventually I scuttled to get it out.
My friend earlier today climbed the ladder on the Brigantine and the game knocked him back off immediately after reaching the top and he dropped a villainous skull inside the wall. You could see a small gold dome sticking out of the wall next to the armory. Luckily I was able to grab it from the outside of the ship through the ladder so scuttling was unnecessary.
That reminded me of when a chicken was stuck in the wall of the galleon. We didn't even know what happened until I was climbing the ladder later on and he stuck his head out of the side of the ship to look at me.