Video comes and goes in G!!

Hi fellows,I have a video in YT which is in the first page od google and its video tab for a keyword,sometimes when I google it it comes up in Google and the video tab without any problem,but yesterday I googld it and it was not there! I even tried to ggogle its direct link, but it was not there, So I thought it was removed by G but when I went to YT SER and tried it, it was there! then after an houre I googled it once again and it was there in google and the video tab!! I even used differnt IP's when it was not there but the same result, Today I got the same thing!! It is very strange to me! Why it does happen?! When I can't find it in G it really is not there at all, but again it comes back and can be found by all its keywords!!!

Google dance, perhaps

Thanks Tommy..

But I don't guess it can cause a video to not bee seen by G even when direct searched! Am I wrong?