Most free mobile games rely on a mixture of ads and in-app purchases to make their money, or they act as a teaser for a paid version. Disney has found a new way to capitalise on the free version of Where’s My Water? though.

An update launched today for the game on iOS and Android adds a free level pack based on Frankenweenie, Disney’s new animated movie.

The levels include visuals and music based on the stop-motion film, as well as a comic panel featuring the movie’s dog Sparky.

It’s a canny strategy on Disney’s part. The Where’s My Water? games have done more than 100m downloads across iOS and Android, and a big, big chunk of those will have been free.

Turning those games into billboards for the parent company’s latest film is a sensible tactic – not least because players will see it as fun content, not an ad.