A friendly bubble appears and says he’s a “very special friend to children everywhere”. It aims to advise them what to do if approached by someone they don’t know.

One of the oldest no-code app builders, Bubble can help you build web and mobile apps without writing a single line of code.

And according to Dave McClure, a venture capitalist at the investment firm and startup accelerator 500 Startups, they're indicative of a bubble — but not where most people think. Bubbles are ...