- "FORK PARKER, that was a big hamster!"
- ―Sam Stone[src]
Mental's Pet Hamster is a boss in Serious Sam: Double D.
Mental's Pet Hamster is a large and long hamster with multiple eyes. It apparently uses the tubes found throughout the previous level to run around and play.
The Pet Hamster has two phases. First, it will try to run over it's target with it's ball. After some damage has been taken, the ball will be destroyed and the next phase will start.
After the ball has been destroyed, the Pet Hamster will retreat to one of the tubes above it. While it is in the tube, it will begin firing shiny orbs through them, which will track the target to an extent. After a certain amount of orbs have been fired, the Pet Hamster will pop out of the tube and run around for a while. It can be jumped on and ridden while it is on the ground, but it will eventually extend spikes from it's body in order to harm whomever is on it.
When the ball has been destroyed, enemies will start appearing in the level. At first, there will only be a Kleer Skeleton in the underground portion. However, as more damage is taken, more Kleers and a Marsh Hopper or two will start appearing in the underground portion, and Chimputees will start appearing above ground in order to hit the player with banana grenades or
- It's rolling phase can be dodged by going underground. It will be completely unable to attack the player while the player is underground. After it rolls away from the player, it gives the player a perfect chance to attack it.
- The orbs fired by the Pet Hamster can be avoided by going underground and running away from the pipes the player. They can't track the player very well while the player is underground and running away from it will make it harder for the balls to track the player because of the length they have to travel. They'll always disappear on their own before they can reach the player because of the amount of space they need to travel over before they can get close to the player.
- Alternatively, the orbs can be jumped over, but this is a bit riskier because of the amount of orbs fired by the Hamster and, later, the banana grenades fired by the Chimputees that spawn it, along with the occasional rogue Marsh Hopper that manages to get to the upper part of the level.
- A powerful gunstack, filled with weapons such as the LM32 Rocket Launcher and MadDog Grenade Launcher, works best against the Pet Hamster. The player needs to quickly damage the Pet Hamster as much as possible, and weapons like those in a gunstack can do so very well.
- Instead of jumping on it's back and shooting at it, shoot it while chasing it. Chasing it will prevent the player from being harmed by it's back spikes and still let the player dodge the banana grenades fired by the Chimputees.
- Other enemies are actually more dangerous than the actual Pet Hamster. The Kleer Skeletons and Marsh Hoppers found underground while running away from the Pet Hamster's orbs can inflict a serious amount of damage, depending on how many there are. Holding down fire while using rapid-fire weapons with a 12 Gauge Shotgun or two can clear out enemies in the underground area, but if there's enough enemies, the player will most likely be damaged once or twice. However, a Kleer jump or an exploding Marsh Hopper is less damaging that being hit by an orb or two.