On December 12, with the assault scheduled for December 24, Carl, Donut, and Mongo enter a mock battle arena to test Donut’s incomplete five-card deck. The system warns them that generated enemies cannot hurt them, but the arena environment can, and that any consumable card used there will be lost. Carl advises Donut to choose the cheapest easy difficulty first because they do not yet know whether Geraldo, the captured Monk Seal totem, will obey them.

Donut chooses an arena environment filled with cheering Nebular spectators and customizes gravity, terrain, and crowd approval. When combat begins, Donut’s cards block her vision until she adjusts the display, leaving Mongo to attack on his own. Mongo destroys the first small purple opponent almost immediately, ending the battle before Carl and Donut can learn much from it.

Carl and Donut retry on easy difficulty in an abandoned version of the arena, this time putting Mongo away so they can test the card system properly. Donut draws four cards, but not Geraldo’s totem card, so Carl explains that a squad leader is vulnerable when no totem is in hand and tells Donut to discard the Combo card. After a ten-second refill, Geraldo’s totem appears, the deck is exhausted, and Carl tells Donut to summon him.

Geraldo appears with stylized kung fu effects, a timer, a health bar, and a team-flag marker. He does not attack Carl or Donut, confirming that the captured totem is controllable in battle. Donut successfully applies the Stout card and one Time Extend card, strengthening Geraldo and extending his duration, but the second Time Extend fails because uncommon totems can hold only two utility cards.

The enemy turns out to be a Squonk, a pathetic level-35 legendary creature that cannot fight and only cries. Geraldo refuses to touch it, and the Squonk rolls over, farts, dissolves into water, and ends combat by itself. After two useless easy-mode fights, Carl concludes they may need to try medium difficulty to get meaningful practice.