Have your freak-shake and eat them too!

Milkshakes topped with donuts, cupcakes and even bacon are becoming popular in Bunbury with businesses offering the decadent treats.

The outrageous creations are known as "freakshakes" and customers are buying them to try the experimental flavours and snap a photo for social media.

Corners on King co-owner Russell Green said the cafe had introduced the milkshakes about a month ago.

"We are always looking for new ideas and we saw them being made in Perth and over east and they are starting to become big," he said.

"We wanted to show Bunbury is up with the rest of the world but we've dubbed ours the Corners Crazy Shake."

Mr Green said the milkshake creations had been received well by the public, particularly online.

"It's a treat, not something you should have daily but every now and again is OK and lots of people are sharing them."

Bunbury CBD business Cake Works has also responded to the craze, coming up with a milkshake with a cupcake on top.

Cake Works owner Maria Contarino says its own version of the "freakshake" is one of its most popular items.

"The idea is to keep it classy," she said.

"We came up with the idea ourselves after seeing trends happening overseas but we didn't want to go down the same path so we came up with something that suits our business."