View once
A feature where an image or video can be opened exactly once and then disappears permanently — it can't be opened again, saved, or (in theory) returned to. WhatsApp, Instagram, and Snapchat have variants.
Mechanic: the sender marks the media as "view once"; the recipient may open it a single time, after which it's replaced with "opened". Use case: sensitive photos, passwords, receipts, fleeting moments — things you don't want lingering in a chat history. Limitation: a screenshot or a second-camera photo bypasses the protection (some apps block screenshots or warn, but it's not watertight). A stricter variant of disappearing messages (one view instead of a timer). Builds on Snapchat's ephemeral legacy but for individual media. Related to disappearing messages and screenshot culture.