A specific feature (or an Easter egg from Valve) was recently discovered in the Steam Controller. A user under the nickname RF3D19 reported that if you drop the gamepad, it might literally start screaming:
If you drop the gamepad in Steam Big Picture mode (onto a pillow or a bed — we're not psychopaths here, are we?), it sometimes plays the "Wilhelm scream." Do with this information what you will, I just felt I had to share it with you urgently.
Judging by the results of community members' experiments, the Steam Controller's "scream" has a cooldown:
It seems to have a cooldown that lasts about a minute, so you can't repeat it over and over without stopping. To clarify: I discovered this by simply throwing the gamepad onto the bed, no devices were harmed in the making of this post.
Initially, it was assumed that the "scream" would only trigger when connected to a PC with Steam Big Picture mode enabled, but experimenters found that this is not a mandatory condition.
You can listen to the "Steam Controller scream" at the following link.