Does this mean that there were ants inside the cake?
Another way of saying it would be "The cake was crawling with ants." i.e. completely covered in ants on the outside and on the inside.
@CK
I have added the sentence "The cake was crawling with ants." as an alternative translation to Japanese sentence No. 225322.
I was not confident enough that 'belebt' could be taken to mean 'crawling' to put it in as a translation of the German sentence.