Colossal Johnson is a free Chrome add-on developed by rblimey. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. This add-on allows users to replace the text 'Boris Johnson' with 'colossal plonker Boris Johnson' or with a custom word of their choice.

With Colossal Johnson, users can easily modify the text on web pages to add a touch of humor or personalization. The add-on provides a simple and straightforward way to make these replacements, making it accessible to users of all technical levels.

All credit for the word-swap code and inspiration goes to Eric Bailey, who initially created the code for replacing words. Rblimey has taken this code and made a few modifications to cater specifically to the replacement of 'Boris Johnson'. This add-on offers a fun and lighthearted way to personalize your browsing experience.