Drifloon, Wild Or Event?

[Trevore 75]

I've been trying to catch a Drifloon for quite some time, and I have no idea where to look. I know that it's in Goldenleaf Town, but the problem is I have no idea where. I tried checking in the grass, but no luck. However, in the characters folder, there is a sprite of an overworld Drifloon, so I assumed that it would be an event. The problem is, I just don't see it anywhere. If anybody caught it before, or knows where it is exactly, I would appreciate it.

[Simon 38]

They can be found in the wild in the grass, but they have a really really low encounter rate I believe. Just gotta keep trying.