During Apple's demo on stage of the iPhone X's Face ID, which is supposed to let a user unlock the phone by looking at it, the feature failed.
The new Face ID feature is supposed to be more accurate and secure than Touch ID, which currently lets iPhone users unlock their devices with a fingerprint. But what happens when it fails? Well, you'll need to enter your passcode instead.
Apple talked a bit about how there are plenty of new features built into the iPhone that should allow this to work in all situations, even in the dark.
Just apparently not on stage in front of a huge audience.