Return of Reckoning

I remember back in the good old days I had an addon that allowed me to make a macro that would swap to the last targeted friendly. It was pretty useful for healing and swapping targets quickly.

But for the life of me I can't recall what the devil it was or the syntax for it. I've spent a few hours over the past few days poking at my mods but I'm still lost. Anybody got a clue?

This can't be done without the implementation of /target