|Act II - Lonalulu, Man in the tavern (Buff-Buff Pep Power required)||Venus' Tear|
Head over to Lonalulu during Act II once you've learn the Buff-Buff Pep Power usable between the Hero and Jade. You'll need to learn Unbridled Blade from the Greatswords tree to acquire it (Jade comes with Puff-Puff already learnt). Head to the tavern once you have the Pep Power to find a man overlooking the sea who wants you to defeat a Night Clubber with this ability.
Sail west from Lonalulu to Insula Incognita and head to the southeast to find these pink monstrosities. Once you have the Hero and Jade Pepped Up, enter into a battle with one of them and wait until it's name is in orange, you need to deal the killing blow with the skill (which will hit for around 500 HP+). Return to the man following your success and report to him to complete the quest.