Like all Pokémon games, Pokémon Snap has some unusual mechanics that set it apart from all the other Pokémon games. In Snap’s case, this is the strange glowing Pokémon that you will see from time to time.
Each level that you visit has the chance of containing glowing Pokémon. These Pokémon have been affected by nearby Illumina flowers, and you will receive more points for photographing them. They are not really special in any other way.
The game also contains items called Illumina Orbs. These can be thrown at Pokémon to cause unique interactions, and will often be the only way to get higher star rated photos of particular Pokémon. Sometimes, the Illumina Orbs can even result in the creation of a totally new type of Pokémon.
Finally, there are special glowing Pokémon that can be found at Illumina Spots, places of great power in the game. Throwing Illumina Orbs at these large Pokémon can result in some stunning photos, and very high scores. Experimenting with these Ilumina Orbs is one of the keys to Pokémon Snap, and is one of the most important things you can do in the game.
Remember, you will only get Illumina Orbs by playing through the game and taking photos of glowing Pokémon and plants, so make sure you are using up your entire camera roll on each expedition.