If you're looking to discuss spoilers for a comic, you should mark-up your post so that other users can opt-in to being spoiled and click or tap to view that content.
If you're writing a review, simply toggle the spoiler setting to present a warning to other users before they open the review. Additionally, this will display a warning at the top.
If you're writing a comment, writing a post, or creating a discussion, you can wrap your text like so: <spoiler>Peter Parker is Spider-Man</spoiler>
Additionally, when adding an image to a comment or post, you can toggle the spoiler setting to blur the images to provide a warning for users.
When discussing spoilers, we ask that you pre-empt the spoiler with a context such as the comic title so others are aware of what lies ahead. Leaving unmarked spoilers is disrespectful to other community members.