When you are done typing your message, select the text you want to have animated by highlighting it.
Click on the "Others" formatting button. (to hide the list, click the button again)
Select the type of formatting you want:
| Spoiler: |
| | Example of "spoiler" (this hides your text that will only be visible when clicked on-think punchlines of jokes.)SPOILER! |
Note: Wow, Index Exponent, Hidden & Random do not work.