You can find the Ferocious Black Tiger on Mirage Isle during the event, which runs through January 27th before maintenance. The tiger gives out two different daily quests, one called Tiger's Gift and one called For the Faction. Only one of these quests requires you to do anything beyond accepting the quest. Tiger’s Gift will complete automatically once you accept it and you will get Ferocious Taffy x2 for your reward. Using a Ferocious Taffy will increase the loot drop rate and XP gained by 80% for 30 minutes.
For the Faction will have you kill 100 monsters of level 50+ and will automatically complete the quest and give you a reward. Players from hostile factions will be on your list of what you must kill and they must be within four levels of your character for it to count, which works similar to ArchePass missions. If you get some kills within instances, they will count towards this quest in addition to party and raid kills. A regular session just might be enough for you to meet your goals if you’re fond of raids and group play. If you complete this quest repeatedly you can also get an achievement reward.
The daily quests reset every day at midnight UTC,through the end of the event. Ferocious Taffy rewards will disappear if not used by February 3rd so be sure to use them and get your bonuses before then. Of course the bonuses they give you will come in handy as you're taking on your kill 100 monsters goals for your second daily quest. The Ferocious Black Tiger will be around until the January 27th maintenance before it too disappears.
For more, see the event announcement over at ArcheAge.