Victini from GO Fest 2020 is not obtainable via a Special Research titled The Feeling of Victory in Pokemon GO.
Update
Niantic has changed the name of the Special Research to Investigate a Mysterious Energy.
There are 6 tasks total requiring Catching Pokemon, Spinning Stops, Catching Specific Types of Pokemon, Hatching Eggs, and more.
Tasks 1/6- Catch 30 Pokémon: Pinap Berry x3
- Spin 30 PokéStops or Gyms: 1000 XP
- Send 10 Gifts to Friends: Stardust x1000
- Final: Great Ball x30, Ralts Encounter, Stardust x1000
- Catch 30 Psychic-type Pokémon: Elgyem Encounter
- Catch 30 Fire-type Pokémon: Darumaka Encounter
- Hatch 3 Eggs: Egg Incubator x1
- Final: 1000 XP, Torchic Encounter, Great Ball x30
- Take a snapshot of your buddy: Poffin x1
- Earn 3 Candies walking with your buddy: Stardust x1000
- Power Up Pokémon 3 times: Hyper Potion x3
- Final: Revive x3, Espeon Encounter, Stardust x1000
- Win 3 Gym Battles: 1000 XP
- Defeat 3 Team GO Rocket Grunts: Lure Module x1
- Power Up Pokémon 3 times: Hyper Potion x3
- Final: Max Potion x3, Victini Encounter, Max Revive x3
- Victini Candy x20 If already have Victini
- Take a Snapshot of Victini: Victini Candy x20
- Catch 30 different species of Pokémon: Incense x1
- Send 3 Gifts to Friends: 1000 XP
- Final: Victini Sticker x5, Stardust x3000, Star Piece x1
- Clear Reward: 3000 XP
- Clear Reward: Stardust * 3000
- Clear Reward: 3000 XP
- Final: Lure Module x1, Victini Candy x20, Lucky Egg x1
