Attention, Pokémon Trainers! Tired of seeing photoshopped images from people claiming they caught a Ditto? Want to catch one of your own? Never you fear! With Niantic's most recent update, you can now catch a Ditto! The way they implemented it is incredibly unique. Ditto will not appear in the wild as itself. They appear as a common Pokémon, such as Rattata and Pidgey. After you catch one, the screen will say "Oh?" such as it does when an egg hatches. The background will turn purple and your Ditto will detransform into its pink gooeyness.
Some people have had difficulty catching Ditto. I found mine when it was a 180 CP Rattata. I was using incense and caught it with a Great Ball (don't judge; I ran out of Poké Balls). Since Ditto is a normal type and disguises itself as a normal type, there is no higher chance of catching it at a certain time, like nighttime.
With this update, Niantic also raised and lowered the CP of the Pokémon trainers currently have. Please, do not be alarmed when you see your 880 CP Pinser became a 1190 CP Pinser or that your 310 CP Raticate became a 289 CP Raticate. They also added a daily catch counter and extra experience points to the first catch of the day!
Play on, Trainers!