Mark_Nguyen said:
It's all non-canon, but an early novel had a Borg Cube popping through the wormhole after stumbling through it. However, the Cube was far too large for what the wormhole could pass through, and so it was barely visible in the event horizon before it imploded. Sisko and the gang quickly noted that because the cube would have essentially disappeared, that it would be quite some time before the skittish Borg sent anything else to investigate. They then continued with the main story, pausing long enough to note that Bashir was on Earth at the time of the first Borg incursion.
Mark