There are several unique and event-themed Pokémon that you can encounter while playing Pokémon Go. One of the more unique ones is the night-scarf-wearing Umbreon, which will only appear during the Pokémon Go Fest 2024 event.

Umbreon with a Nightscarf will only appear briefly and only during specific encounters. If you want the best chance of catching this Pokémon, purchase a ticket for the Pokémon Go Fest 2024 Global event. It will appear at multiple points during the event, primarily on the first day. It may also appear on the second day, but the chances may not be as high.

Umbreon wearing a night scarf will make its debut during the first day of Pokémon Go Fest 2024 on July 13. When the event falls, it can appear during the Creeping Dusk and Darkest Night habitat rotations, but only if you have incense on your character and have purchased the ticket. If you haven't purchased the ticket and don't activate incense during these rotations, Umbreon will not appear and you're likely to miss it.

Alternatively, Umbreon does spawn in three-star raids. You can find them scattered around your local area during the Pokémon Go event, offering another way to potentially encounter this Pokémon. You're more likely to find them waiting at a Gym than randomly spawning in the wild while using incense.