CREATE TABLE table_11655 ("Series #" FLOAT, "Season #" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" FLOAT)

Who wrote series number 99?
SELECT "Written by" FROM table_11655 WHERE "Series #" = '99'
SELECT "Written by" FROM "table_11655" WHERE "Series #" = '99'