It’s one Lego kit, a collection of small plastic bricks and related accessories. What could it cost? The answer, it turns out, could be thousands of dollars.

Lego kits and minifigures, figurines that are a little over 1.5 inches tall, are commanding high prices on the secondary market, with some, like the LEGO San Diego Comic-Con 2013 Spider-Man, valued as high as $16,846.

The children’s toys have even become something of an investing opportunity for those savvy enough to know what to look for.

But with the eye-popping price tags comes a dark side: Lego kits have become a hot commodity on the black market and the target of brazen thieves.

Last year, burglars hit Bricks & Minifigs outlets in California. Thieves made off with at least $100,000 worth of Lego kits and accessories.

Last month, the Alameda County Sheriff’s Office in California recovered nearly 200 Lego sets after arresting a person in connection with a burglary at Crush Comics, a comic book store in Castro Valley, Calif.