- In the PSA mission "Secret of the Fur," you're warned about a monster that you must track down and identify. It broke the coffee machine in the Coffee Shop. When you enter the Ski Lodge, you'll see a terrified penguin hiding under the couch cushions and telling you about a monster outside. If you go outside, you'll see a shadow of a tall creature with claws that moves rather smoothly. As soon as you enter the room, ominous loud music starts blaring, which can be easily startling as the missions have no music besides a short loop that plays occasionally.
- There's a very rare chance that in Aqua Grabber's Clam Waters level, the screen will shake and a giant, shadowy squid will shoot up into view before swimming away. It used to make a loud screech, but the sound was removed.
- During Operation: Hot Sauce, the Pizza Parlor's music was changed to a slowed down, distorted version of its usual theme. It stays even after you beat the mission.
- The Halloween parties were rather spooky. One recurring party room was the Haunted House, which involved moving statue heads, a coffin of puffles (still alive), and floating instruments that played at random. There was a door that you could open to reveal some colored lights and then a random event, including a pumpkin that grows rapidly before the door closes or a penguin skeleton that shakes.
- The Medieval Party 2012 added a room called Dragon Path. If you idle long enough, you hear a surprisingly loud demonic screech.
- Operation: Blackout is Club Penguin's Darkest Hour. Herbert successfully blocks out the sun, and as the party goes on, the island gets increasingly darker and snow starts piling up. The EPF agents are captured by Herbert, and eventually, you're the only one left. Even the login screens have intense close-ups of Herbert saying phrases like "Enjoy it before I destroy it!" and "The island is DOOMED!"
- The 10th Anniversary Party has robots of the mascots that tell you about past parties. Eventually, they start breaking down and turning evil, with glowing eyes and evil expressions. Their dialogue cuts off halfway through with errors and corrupted text.
Nightmare Fuel / Club Penguin