Mordecai keeps looking at the one floating over Katia and wants the circumstances explained first.
Mordecai zeroes in on the golden skull floating above Katia Grim again, and when he lays out the order in which he wants the missing week explained, the skulls come first: the circumstances regarding the player-killer skulls Carl and Katia are both carrying, then how Katia became the highest-level crawler in the party, then everybody's new skills. He never gets through the list — the Night Wyrm's Ring on Carl's hand derails him before Carl can start.
A gold skull rotating slowly above a crawler's head, visible to everyone.
The public marker of a crawler who has killed another crawler.