The text of Joshua 4:18 holds an oddity:
וַ֠יְהִי בעלות [כַּעֲל֨וֹת] הַכֹּהֲנִ֜ים נֹשְׂאֵ֨י אֲר֤וֹן בְּרִית־יְהוָה֙ מִתּ֣וֹךְ הַיַּרְדֵּ֔ן נִתְּק֗וּ כַּפּוֹת֙ רַגְלֵ֣י הַכֹּהֲנִ֔ים אֶ֖ל הֶחָרָבָ֑ה וַיָּשֻׁ֤בוּ מֵֽי־הַיַּרְדֵּן֙ לִמְקוֹמָ֔ם וַיֵּלְכ֥וּ כִתְמוֹל־שִׁלְשׁ֖וֹם עַל־כָּל־גְּדוֹתָֽיו׃
or in the JPS 1917 translation,
And it came to pass, as the priests that bore the ark of the covenant of the LORD came up out of the midst of the Jordan, as soon as the soles of the priests' feet were drawn up unto the dry ground, that the waters of the Jordan returned unto their place, and went over all its banks, as aforetime.
I have put in bold the bit that is curious. The "plain sense" here would appear to be that the priests were, somehow, "carried" or lifted out of the stream bed, although this sense is usually not conveyed in modern translations. The 1985 JPS Tanakh has "...and the feet of the priests stepped onto the dry ground,..." at this point.
However, the text was taken at "face value" by Rashi, who offered this comment:
the soles of the priests’ feet were lifted up: from the water to the dry land which was beside them, and the waters returned to their place. Hence, the Ark is found to be on one side and Israel on the other side. Accordingly, the Ark lifted its bearers and passed over. And concerning this matter, Uzzah was punished when he took hold of the Ark. If it bore its bearers, can it not be deduced by a fortiori conclusion that it can bear itself?
So clearly Rashi believes the the Ark had the power to "levitate", and even then to bear the priests on to dry land. He uses this to explain the case of divine anger against Uzzah in 2 Samuel 6, since if this is true -- that the Ark can "bear itself" -- then Uzzah's intervention was not required.
Finally, then, my question is this: was Rashi anticipated or followed in this interpretation of Joshua 4:18? I have checked the modern "scholarly" commentaries fairly carefully, and there isn't a hint of this anywhere. (I haven't checked my Miqra'ot Gedolot, though.) I would be fascinated to know if there is a larger tradition of interpretation in the vein of Rashi's comment.