You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "Hydra is an album by Within Temptation and contains guest appearances by an American metalcore vocalist best known for being the vocalist of what two bands?" whose answer is Killswitch Engage and Blood Has Been Shed.
Each document should contain about 30 words, and these documents should contain useful information.

Query: guest vocalist on Within Temptation Hydra album
Useful Output:

Doc 1: Directed by Patric Ullaeus and featuring guest vocals from Howard Jones (ex-KILLSWITCH ENGAGE / DEVIL YOU KNOW) plus the adrenaline-inducing
Doc 2: In a less surprising collaboration, former Nightwish singer Tarja Turunen appears on the single “Paradise (What About Us)”, which features some
Doc 3: The second single released from the album, this features guest vocals from Howard Jones (ex-Killswitch Engage) and his powerful and distinctive
Doc 4: The guest vocals for the song “And We Run” is provided by rapper Xzibit. Pimp My Ride anyone? Yeah, that Xzibit. Chiming in around the midway
Doc 5: Guest musicians. Howard Jones – vocals on “Dangerous” Xzibit – vocals on “And We Run” Tarja Turunen – vocals on “Paradise (What About Us?)”