What's "ended in a disaster" in Chinese?
More native way is 災難收場.

～收場：


喜劇收場
悲劇收場
混亂收場


Another way is 大災難結局, for some big ending in drama and film.

大～結局 ：


大團圓結局


In writing, it could be 災難結尾.

～結尾：


歡喜結尾


You might use other words like 災難收尾, 災難而終.