In Phineas and Ferb, we meet the talking zebra a lot and it's a character of Candace's imagination. But, why did it call Candace "Kevin"? That's a male name and has no relation to Candace. Is this some reference to any other show, etc.?
From the Phineas and Ferb wikia:
It is currently unknown why the Talking Zebra calls Candace "Kevin". Although, as revealed in the Phineas and Ferb The Movie: Across the 2nd Dimension, Kevin may actually be the Candace of the Zebra's dimension. However, how, or even why the zebra seems to cross dimensions is unknown.
Notice the silhouette of the image where it bears striking resemblance to Candace...
There is also a passing reference where the Zebra says "I voted for you Kevin!" with Candace's face...
There are multiple references. We can say Easter Eggs.
Candace's last name is Flynn. Zebra calls her Kevin every time which makes her Kevin Flynn. There are some famous people with the same name.
Kevin Flynn is a Canadian politician. (This could be a reference to "I voted for you Kevin" in Nerds of a Feather). This is continued by showing a newspaper clipping Kevin wins election in the song "Brand New Reality".