Strange easter egg in Google search?

Surprisingly to see such error in google search, when i searched for' advanced persitent threat' I get: Server Error We're sorry but it appears that there has been an internal server error while processing your request. Our engineers have been notified and are working to resolve the issue. Please try again later.

https://www.google.ro/search?client=tablet-android-samsung&ins=&q=advanced%20persitent%20threat