An exclamation used to signify understanding someone. From the anime series Elf Princess Rane (aka Fairy Princess Ren). Can also be used as a general exclamation with no actual meaning.
"I see. Then I'll file an official complaint with the Fire Department. Gotchabaguse!"
"Takuma-sama! Takuma-sama! Gotchabaguse! Gotchabagotchabaguse!!"