Candace is telling Stacy about how she saw Perry as a secret agent in The Ballad of BadBeard, but saw it as a hancullation, while Stacy knows it's actually real.
I find it funny how Candace dreams about Perry being an agent, while Stacy know's it's real.
P.S. I really liked that fact that Stacy now knows Perry's secret in Happy Birthday, Isabella, I might make another deviation related to it.
Candace and Stacy (c) Disney, Dan, and Swampy