Mallet Mash (キノコだ でかハンマー lit. Mushroom Big Hammer in Japanese) is the twenty-fifth level in Crash Bash, the third stage in the fifth warp room, and the third Medieval Mayhem arena. It can be unlocked by obtaining 21 gold relics. The goal to is to smash the most mushrooms. Regular mushrooms are worth 2, 3, or 5 points and gold mushrooms are worth 10, 15, or 20.
- Purple ? - These crates contain either speedy boots or shock waves and can be smashed by players.
- Speedy Boots - Players with this powerup will move faster temporarily. Lasts for six seconds.
- Shock Wave - The player will smash more powerfully.
- Mushrooms - Most mushrooms will be worth 2 points (or 10 if gold). If a mushroom has been standing for three seconds, it begins to shake, and is worth 3 points (or 15 if it's gold). If it is standing for five seconds, it shakes more violently, and is worth 5 points (or 20 if it's gold). If a mushroom is left standing for six seconds, it explodes and cannot be smashed for points.
- Trophy: Win 3 times.
- Gem: Player 1 starts at 80 points while the opponents start at 60 points. For 2P story, Team 1 starts at 180 points and Team 2 starts at 120 points.
- Crystal: Your opponents will have shock waves that stun you if they hit you.
- Gold Relic: Win 2 times against the champions of the arena.
- Platinum Relic: Win 3 times against the champions.