Preheat the oven to 350°F, cook the cauliflower in salted water, and then let it cool slightly.
Combine the ground beef, bread crumbs, egg, onion, parsley, milk, mustard, paprika, salt, and pepper and mix well.
Put the cauliflower in a pan and shape the ground beef mixture around it.
Add some red food coloring to a pot of water and heat to about 175°F. Tap a hard-boiled egg with a spoon (but don't break the shell) and place it in the pot of water for 45 minutes. Let the egg cool and then peel it.
Cut the egg in half and stick the halves in the ground beef as 'eyeballs.' Put the pan in the oven and cook for 30 minutes.
Use the olives to make pupils for the eyes and stick them to the eggs with mayonnaise. For the final ghoulish touch, pour tomato sauce 'blood' over the cauliflower brain.