Physics with smartphone camera explains spider behavior
If you use a second smartphone camera to look at the lens side of your iPhone, your second phone can probably see the infrared light emitted by the LIDAR of the iPhone, and "translate" it to a wavelength you can see on the second phone's display.
I noticed this phenomenon when using my Samsung phone to look at an operating automotive LIDAR scanner. The LIDAR light was invidible to the eye, but showed up on my phone's display.