Curse of Insomnia

First of all, regular Phantom spawning gets removed (or heavily increased to something like 10 sleepless nights). Next, slaying the Wandering Trader will cast you the Curse of Insomnia, which will make you unable to sleep for the following few nights, cannot be removed with a milk bucket and spawn Phantoms relentlessly. The Wandering Trader could also sell you some Insomnia potion to peacefully self inflict the ailment, which can be healed with a milk bucket.