OK, as of yesterday my phone (a Moto Droid Z) has undergone some type of bizarre demonic possession that makes it die when I put it in my pocket. And no, I didn't drop/submerge/etc. the phone. That would make this easier to understand.
In a bit more detail, if I put the phone in my pocket for just a few minutes, the entire screen turns a strange shade of off-while and undergoes a series of increasing/decreasing brightness events followed by lines on the screen and eventually a reboot. It's completely unresponsive while all of this is going one.
These symptoms look like the screen is going bad on a physical level BUT... once the phone reboots the screen works perfectly again. No weird artifacts, touch operations work fine, etc.
I have personally tested the phone for several hours when it is left out of my pocket or any other enclosure and it will work fine for hours at a time. Put it back in my pocket: Back to crashed in just a minute or two. Incidentally, I have checked the phone and it's not overheating or anything like that. These crashes happen when the phone is idle and it's not getting too hot.
Here's my best guess: Something with the proximity sensor has gone way way wrong and when the phone detects that it is in an enclosed space like my pocket, the whole system is spazzing out for whatever reason. When it's left out, the proximity sensor is not producing the same readings and the phone doesn't crash. But that's just a guess.
Anybody else encounter a problem like this?