[Congratulations, you have found the intangible voicemail box of Bill Cipher. However you managed to find this nonexistent channel, only the hiss of static and what sounds suspiciously like distant screams will greet you.
ONE DOES NOT CONTACT A DREAM DEMON- HE contacts you. BUT With a well placed summon, screaming into the void, or perhaps if you have something of interest to offer, he just may just answer your call before you even make it. After all, Bill IS ALWAYS WATCHING...]