meet Disqus’s new spoiler tag (for hiding them)
All the details can be found at Disqus, but — spoiler! — basically you just use this bit of HTML in your comment:
<spoiler>Spoiler goes here.</spoiler>
And the spoilery thing will be hidden by a gray bar until you hover over it (on a PC) or tap it (on a mobile device).
Feel free to play around with it in the comments below.