Buy A Taunt And Equip It In > Customize - On The Main Menu.
(I Think They Are Like 1500 In-Game Currency)
- If You're Using A Keyboard Default Hotkey Is [v]
Start The Game As A Ghost
- Possess The Nearest Thing And Start Mashing The Taunt Button.
If You Are Quick Enough You Should Be Able To Pop The Achievement Before The Hunters Spawn In, So There's No Danger To You.
Good Luck!