ZAAAAAA ZAAAAAAAAAAAAA is a way of expressing happiness, excitement, joy ect. ZAAAAAA ZAAAAAAAAAAAAA is spelled with six A's in the first ZA and fifteen A's in the second ZA as repeated numerous times by the original creator. The original creator of ZAAAAAA ZAAAAAAAAAAAAA is Collin Fiol. (a.k.a the awesome merch dude from the band Late Nite Reading)
person 1: congratulations you just won a million dollar's
person 2: ZAAAAAA ZAAAAAAAAAAAAAAA!!!
person 1: huh?
person 2: look it up on urban dictionary.