The strongest Typhlosion will appear in Pokemon Scarlet and Violet as an Tera Raid event. It will be a 7-star raid, and Typhlosion will have a Ghost Tera Type. This would make it similar to Hisuian Typhlosion if you Terastallize. However, it will still look like the normal Johto Typhlosion. [Thanks, Inside Games!]
You’ll be able to find the 7-star Ghost Tera Typhlosion raids from black crystal dens around Paldea. Since Typhlosion is not native to Paldea, this event (and future ones featuring Typhlosion) will be one of the few chances players will have to catch the Pokemon. Typhlosion is one of the starter Pokemon from both Pokemon Gold/Silver and Pokemon Legends Arceus. Since previous raids put Samurott and Decidueye in the game, players who participated in all of them should have the three Arceus starters.
The Typhlosion Tera Raid in Pokemon Scarlet and Violet will run from April 14-17, 2023. It will then re-run from April 21-24, 2023. You will only be able to capture one Typhlosion per save. This means that if you caught one in the first few days of the raid, you won’t be able to get another one during the re-run.
Pokemon Scarlet and Violet are available on the Nintendo Switch.