Have an Octotastic day is a creative, light-hearted expression that plays on the word ‘octopus’ and the adjective ‘fantastic’. It essentially means “Have a fantastic day!” while adding a playful and original touch.

It's often used in humorous, nautical or octopus-themed contexts (as in advertising campaigns, games or brands with an octopus as mascot). In short, it's a fun way to wish a happy day with a bit of whimsy!

In the context of GitHub, “Have an Octotastic day!” refers to their iconic mascot, Octocat (a stylized octopus-cat).

It's a fun way for GitHub to personalize their communication and stay true to their relaxed, creative image. The phrase plays on the theme of their mascot to encourage users to have a “fantastic” and productive day, probably coding or collaborating on projects. 🐙✨

In short, it's both a nod to their branding and an engaging way to wish their tech-savvy community a good day!