"Franz Xaver Messerschmidt was labelled mad in his own century and by the time he died in 1783 he had produced sixty four remarkable busts of himself which reflected his state of mind and his attempt to alleviate his perplexing ailments."I thought the picture up top would be perfect for a Brazen Head (even though it's made of tin). But the others are intriguing too. This one:
seems perfect as a representation of the mad emperor that called for the construction of your favorite megadungeon.