My favorite is the one where the SA-X is running back and forth with Samus in morph ball RIGHT in front of the SA-X. XD And the one with the missiles is great too.
I changed the value that controls what he's doing so that it's always shooting super missiles, but of course, the game only has so many RAM blocks to store those missile in
I figure they thought SA-X encounters were so rare and you were supposed to run away from it anyway that they didn't bother programming a halfway decent AI.