This may not be 100% analogous, but we do see a case of 2 natural enemies uniting against a common foe.
Ice and Fire united in order to bring the plague of hail upon the Egyptians. From Rashi (Shemot 9:24) quoting the Tanchumah:
flaming within the hail: [This was] a miracle within a miracle. The fire and hail intermingled. Although hail is water, to perform the will of their Maker they made peace between themselves [that the hail did not extinguish the fire nor did the fire melt the hail]. — [from Tanchuma, Va’era 14]
The emphasis there however, is that the peace was made because of G-d, as opposed to being because of the Egyptians.
The Tanchuma (Va'era 14) does emphasize the enemies a little more:
משל למה הדבר דומה, לשני לגיונות קשין ששונאין זה את זה. לימים הגיע זמן מלחמתו של מלך. מה עשה המלך. עשה שלום ביניהם והלכו ועשו שליחות המלך. כך אש וברד צהובין זה לזה. כיון שהגיע זמן מלחמה של מצרים, עשה הקדוש ברוך הוא שלום ביניהם והכו במצרים. הוי, ויהי ברד ואש מתלקחת בתוך הברד
A Parable is given: There were two tough legions that hated one another. One day the time to fight the war of the king arrived. What did the king do? He made peace between them and they went and did the will of the king.
Likewise, fire and ice are hostile to one another. When it came time to fight the war of Egypt, G-d made peace between them and the struck Egypt. "And there was hail, and fire flaming within the hail" (Shemot 9:24)