What's going on here? מַה זֶה?

Bil’am’s donkey sees an angel of God, holding a sword. This makes the donkey scared, and it swerves off the road (Bemidbar 22:23).

What exactly did the donkey see? Did it really see something that Bil’am wasn’t able to see?

Ramban says the donkey didn’t see anything unusual. After all, angels don’t have physical bodies! What happened is that the donkey felt something unusual and became scared.
Rashi says God performed a miracle that allowed the donkey to see on a special, deeper level of perception. So its eyes actually saw an angel.

-------------------

-------------------