Skulls

Skulls are NPCs in Dungeons. You can talk to them by right-clicking on them, and some skulls will give you a Redstone Key instead of granting dialogue. Other than that they serve no other use other than to add lore to the game.

You can speak to the Skulls on the Wither Doors, but the ones on the Blood Door can't be interacted with.

Wither Skull

 * "Monsters with a star next to their name have Wither Keys... sometimes."
 * "If you didn't find the Wither Key yet, it probably means you need to go back!"
 * "That's a door, and I keep the door... there."
 * "This is the way."

Green Skull

 * "I'm feeling a bit queasy."
 * "Gotta go green!"
 * "Anyone else feel sick in here?"
 * "Green would look good on you."

Blue Skull

 * "Some guy called Pedro did this to us."
 * "I think we are all victims of a terrible joke."
 * "Wait I'm blue too?? I must have been sleeping."

Yellow Skull

 * "Touch my treasure and you will get it!"
 * "Ah man, this is the death! I'm loving it."

Red Skull

 * "They all copied me."
 * "I'm not red, I'm magenta."