Anvils are used in Crash Bash. They appear in most Polar Push challenges as well as in Space Bash and Snow Bash. In Polar Push, they can be obtained by going into the robot's laser beam (or Uka Uka in Melt Panic). Once obtained, an alarming sound starts playing gradually getting faster and faster.
The player who has the anvil must quickly pass it onto someone else by charging into another player. When the sound stops, the player with the anvil is crushed and out of the game. In Polar Push minigames, the sound lasts for ten seconds. In Space Bash and Snow Bash, it is pretty much the same, but the sound only lasts for eight seconds.