The Scratch Cat is the mascot of Scratch and the default sprite when opening a new Scratch project, though this can be changed. It is also the outline for the default icon of new Scratch accounts, replacing a previous version that showed a human silhouette. The Scratch Cat is a trademark of MIT.
There are many varieties of the Scratch Cat's look. Some are below:
Mixture of the Scratch Cat and Gobo
Use in Projects
Over 35,000 projects use the Scratch Cat in its most well-known form (the costume named 'cat1-a'), making it the second most used image in Scratch from Scratch 1.3 upwards. The high usage of the image is most probably because it is the default starting image for Scratch.
The image is often used as a narrator for a project (particularly tutorial projects), as it is such a well-known image. It is also frequently used as an interviewee in talk-show-style projects. As well as these, it also serves many other uses.
When a user attempts to view a project that has been disabled by the Scratch Team, the user will see an animation of the Scratch Cat explaining that the project is not suitable for all members of the Scratch Community and has thus been removed. However, this has been replaced with a simple "This project has been removed" page, with no animation at all. The animation of the Scratch cat can be downloaded here.
_meow_ Scratch Cat Image
In a comment, if a user types
_meow_, it will turn into a Scratch Cat head. This image became popular in September 2011.
Since being discovered, it has been spammed a lot on people's projects. Some Scratchers use them for awarding someone if they did a great job or worked really hard but some just write "_meow_" over and over again. This can make it hard to read comments and forum posts, along with other things. This bothers some people, and is frowned upon. 
Can't Connect to Server
When you can't connect to the Scratch website server, a picture of the Scratch Cat appears with a box of blocks, and the screen displays "Oh noes, our server is scratching its head".
- Scratch 1.4 Reference Guide > Scratch Interface > New Sprites
- Forum thread: Thanks to Yickpoo for creating the new default avatar
- Scratch 1.4 License