As much as his villainous persona depicts him as a vengeful loner, one of DOOM's biggest strengths is his tendency to shine in the guest-appearance spotlight — after all, he began his recording career as a guest, dropping Afrocentric knowledge as Zev Love X on 3rd Bass' industry-baiting classic "The Gas Face" 20 years ago.

Mixtape/compilation Unexpected Guests, assembled with the same seamless-transition segues and comic-book interludes as his best albums, exists for the sole purpose of highlighting those frequent times where DOOM played well with others. Some are familiar — a couple Dilla-produced tracks, the Ghostface team-up "Angels" (in its mostly drum-free pre-Born Like This mix) and Operation: Doomsday highlight "? (feat. Kurious)" are longtime fan favorites. But the one-offs, drop-ins and cameos collected here come from a long line of work that frequently saw DOOM popping up wherever he seemed to fit. Which was just about anywhere: this is DOOM at his most versatile, swapping criminal-enterprise scenarios with Wu-family peers, lyrically sparring with backpacker favorites, and spitting smart-mouth punchlines about sex and beer. It's a wide-ranging collection, but there's one constant: the arch, intricate wordplay that made DOOM a cult (anti)hero in the ’00s.