Slimy

Air Raid Siren
Sound from an air raid siren.

Toilet Flush
Sound of toilet flush.

Here we go
The Joker, played by Heath Ledger gets ready to execute a plan.

Ha ha ha
The Joker, played by Heath Ledger laughs

Hysterical laughing
This is the sound of a female laughing hysterically.

Mu hah hah - Evil Laugh
An evil laugh.