Sep 3, 2018
With regards to the new Rot Hulk. If I sacrifice it before its ETB trigger resolves, can I return Rot Hulk and get another trigger? Or do I have to choose targets before I can place the trigger on the stack
You have to choose targets when the trigger goes on the stack, which is before you have priority to do anything that would let you sacrifice Rot Hulk.
The only way for Rot Hulk to be able to be returned by its own ability would be by it dying to state-based actions somehow before anyone receives priority, such as if it were legendary and you already controlled another one.