“Fica, vai ter bolo!” is a brazilian meme that means “Stay, it´s going to have cake”, a typical grandma phrase. It was created by two Twitter users @nairbello and @hebecamargo, fake profiles for the brazilian TV celebrities Nair Bello and Hebe Camargo. These two celebrities are very famous in Brazil and they are old womans, that´s why they created this grandmother phrase.
A famous brazilian magazine Veja São Paulo made an article, in portuguese, about the meme: http://vejasp.abril.com.br/materia/tumblr-dicas