The bagpipes comprise a bag made from a pig's bladder, mouthpiece and drone pipe. Pigs were associated with gluttony, and this image may have been warning against overindulgence. It could also be a joke, as the boar is playing an instrument made from its own body.
Boar playing bagpipes
Explore other bosses in this area
Current boss highlighted in red. Click/touch other bosses for details.