For every pokemon you encounter on your adventure to become the world’s greatest trainer, you have about a 1 in 8000 chance of that pokemon being ‘shiny’, or a different color than normal.

Pokemon GO's Beloved Buddies features several Pokemon who will receive boosted shiny rates throughout the event.

The care that has gone into creating new animated sprites for every Pokemon that ... You can spend tickets (all earned in-game) on hatching eggs from Legendary or shiny machines.