I just unplugged the Dell Streak after a few hours of charging through a wall outlet. The screen turned on as soon as it was disconnected like it always does and since I wasn't planning on using it right then, I pressed the power button like I always do to turn off the screen and put the device into standby.
The screen stayed on.
So I pressed the button again, this time looking at it to make sure I wasn't accidentally pressing the camera shutter button right beside it; the power button is more recessed than the shutter button, so I occasionally hit the wrong one when blindly feeling for it.
I pressed the power button with the same amount of force I always do: just a quick and light press . . . which promptly sent the Streak into a full-body vibrating frenzy.
I'm accustomed to the capacitive buttons vibrating when pressed (there's no way to disable this in the settings), so to feel the entire device buzzing in my hands for no reason was very alarming. The screen was still on, too, so I pressed the button again hoping that the vibration would stop and the screen would turn off.
So I pressed the button again. And again. And again. And again.
Since the Streak automatically powers off when the back cover is not just removed but also simply slid out of its locked position, I turned the vibrating device over and slid the back cover down. The buzzing continued, so I removed the back cover completely. The vibration went on nice and strong, so I finally just pulled out the battery after momentarily worrying that something bad would happen if I stuck my finger in there.
Thankfully this last step worked (this post would've been about gadget exorcism if it hadn't!). The Streak booted up normally after I put the battery back in and has been behaving normally so far. I don't know what caused the issue to begin with, but it's made me feel a little anxious every time I press the power button, which is something I do countless times per day!