Monster Surprised You

Monster Surprised You is Disc 2, Track 2 on the Xenoblade2 Original Soundtrack and Disc 7, Track 2 on the Xenoblade Chronicles Original Soundtrack Trinity Box. It plays in the following battles, and often (but not always) in the cutscenes immediately prior:

Main plot

 * The Megalo Aligo on the Ancient Ship.
 * on the Titan Battleship.
 * in Uraya.
 * The Elder Arachno in Uraya.
 * Menacing Jo, Cartbreaker Grzeg, and Benjamin the Brain in Gormott.
 * in Alba Cavanich.
 * in the Old Factory.
 * Aeshma's power lines in Temperantia.
 * in Temperantia.
 * Addam's Phantasms in the Spirit Crucible Elpys.
 * The Deadfire Guldo in the Land of Morytha.
 * The Darkblood Guldos in the Land of Morytha.

Quests

 * Weirdo Gillick, Lackey Errol, and Lackey Neb in Azami's Blade Quest All's Fair.
 * The Arrogant Behemoth in Dagas's Blade Quest Lost Kingdom.
 * The Sarta Garluses in Dahlia's Blade Quest Fly in the Ointment.
 * The Nanda Arachno in Electra's Blade Quest Go for it, Electra!.
 * Angry Rvano and his minions in Floren's Blade Quest Nature Boy.
 * The Evil Sandstream in Godfrey's Blade Quest Flames of Justice.
 * Herald Unbound in her Blade Quest The Calm and the Storm.
 * The fight against the multiple waves of Brius Tirkin, Skom Tirkin, Matchul Tirkin and Nongl Tirkin in Kasandra's Blade Quest Our Daily Bread.
 * The Dagra Guldo in KOS-MOS's Blade Quest Artificial Intelligence.
 * The Brionac Ghost, Reys and Rados in Newt's Blade Quest Newt Recruits.
 * Lethal Bradly and his minions in Perceval's Blade Quest Failure and Success.
 * The Zohak, Vallent and Gardyll Drivers in Perun's Blade Quest Eternal Spirit.
 * The Lindwurm Drake, Cougar and Hinds in the same quest.
 * Vengeful Waldemar and his minions in Theory and Praxis's second Blade Quest, Blade-Sharp Memory.
 * Thanatobeast Andraz in Zenobia's Blade Quest, A Real Challenge.
 * The Dross, Scram and Larm Ignas in Crossette's Blade Quest, Bright Spark.
 * The Gigalid, Scram, Riot and Trauv Ignas in the same quest.
 * Akatsuki's Driver in the quest Insurgent Investigations.
 * Doctrinaire Erebos in the quest The Riddle on the Wall.
 * The Brionac Seàirdeant, Head, Neslis, and Stellar Scout in the quest Farewell, Good Friend.
 * Cloud Sea Tyrant Nero in the DLC quest Cleared of All Charges.
 * The Sakryfyce Igna, Vyktym Igna, and Blood-Crazed Stalker in the DLC quest A Mercenary's Honor.
 * The first fight against Pelagic Vincent in the DLC quest Merclibay's Mightiest.
 * Celestial Bailey, Telluric Desirée, and (the second) Pelagic Vincent in the same quest.
 * The Nameless Sentinel in the DLC quest Mystery Launch Codes.
 * Vengeful Zadazan during Bana's Revenge.

Torna ~ The Golden Country

 * in Torigoth Village.
 * in Torigoth.
 * The in Aletta (for the first phase of the battle).