Tabby Cat is a unique Firefox extension that adds playful virtual cats to your browsing experience. These animated tabby cats engage with users by blinking, sleeping, and responding to interactions, creating a lively atmosphere. Users can also capture snapshots of their favorite cats, preserving their virtual companions for future enjoyment. The extension offers a delightful way to personalize the browser while keeping the user entertained.

In addition to the main features, Tabby Cat includes a fun surprise element where cats may leave goodies for users. Some toys in the extension can attract special combo kitties, which are adorable baby cats that appear under specific conditions. This adds an element of discovery and excitement for users as they explore different combinations of goodies to find all the combo kitties.