Who's Eyeing Who?

I came upon this scene this morning:

Two predators sizing each other up?

A young Northern Gray Tree Frog.

An adult Redfooted Cannibalfly, a critter that usually hunts other insects.

A tiny frog and a giant fly. Both about the same size.

Alas, the battle royal was not to be. The fly, perhaps spooked by my presence, flew off. It is an hour or so later as I type, the frog is still there. 

Dreaming of the feast that wasn't?