Put two vertical bars on each side of the text, as in ||the butler did it||, and it stays hidden until someone clicks or taps it. You can mark images and files as spoilers too.
How do I mark a spoiler on Fluxer?
Wrap the words you want to hide in || on both sides. To hide several lines at once, put || on a line of its own before them and another after them.
||
The butler did it.
He hid the key in the piano.
||
In the web and desktop apps, you can also type /spoiler followed by your message to hide the whole message as a spoiler when you send it to the channel.
Can I mark an image as a spoiler?
Yes. Before you send an image, video or other file, edit the attachment and turn on "Mark as spoiler", and it stays hidden until someone clicks or taps it. This works in the web, desktop, iOS and Android apps, for every kind of file you can send.
Can I always see spoilers without clicking?
Yes. Under "Spoiler content" in the "Chat" settings of the web and desktop apps, you can choose "Always show spoiler content", or only show it right away in channels where you have the "Manage messages" permission. The setting only changes what you see, and other people still see the spoiler hidden until they click or tap it.