an explanation of うなぎ文(all in Japanese)
うなぎ
In a family conference to discuss the inheritance from their father
長男:俺は会社を貰うよ。
長女:じゃああたしはこの家にするわ。
次男:なら僕はビルだ。
In this case, the second son can't omit 僕は in his words, since just to say ビルだ is unclear who the subject is or who the one to inherit the building is.