Tiny Japanese monsters have suddenly invaded Denver. If you download the free Pokémon Go app, you'll see them popping up all over town: high-tech versions of the characters introduced to America on Pokémon cards two decades ago.

While the app leaves something to be desired on a technological level (the augmented-reality game has had server failure since its launch last week), it's worth the glitches to see a Diglet dig its way through the fountains at Union Station. This blurring of reality and animation feels like magic; it's so compelling that you might find yourself holding your phone up high as you head to a public bathrooms, just in case you run into another Pokémon. 
Don't overthink it: The point of Pokémon Go is simply to catch 'em all. A "incense" will lure the Pokémon to you, and your phone will buzz when a Pokémon pops up. When you click on it, the app takes you to a Pokéball that you flick forward (your index finger is most effective for aiming). The Pokéstops are cubes floating in the air, often in front of recognizable schools, statues, murals and storefronts. They may contain extra Pokéballs and other necessities, and if they are glowing pink with little petals surrounding them, that means the Pokéstop has the Lure Module in action for the next thirty minutes. Running into one of those stops will pretty much guarantee a Pokémon frenzy.

Otherwise, you simply stand on a 3-D map of Denver and wait to see what mysterious creature next crosses your path. 

Pokémon Go at your own risk, though. Passersby may think you're insane when they see you holding up your phone, trying to catch monsters that are invisible to them. You must also be careful not to walk into traffic. When you first log in, the app warns: "Remember to be alert at all times. Stay aware of your surroundings." And never Pokémon Go and drive. (Texting is bad enough.) A recent hoax reported that a driver had  caused a pile-up on the highway while he was attempting to catch a rogue Pikachu. 

It's all pointless and hilarious and addictive. There are training stations randomly placed around town where you can practice once you've reached level five. Called "Gyms," they often are located at cool Denver landmarks, such as the one in the center of Union Station. 

For more Pokémon Go action, mark your calendars for a Pokémon Go Meet-up on July 17 as well as a Pokémon Go Bar Crawl set for August 20.