Hypersmurf
Moderatarrrrh...
What if you're standing in an AMF while your custom spell expires? Do you take the d6 subdual? when you leave the field? or not at all?
That one I'm not sure about

And it could come up, because there are a few spells that have effects on termination. Righteous Wrath of the Faithful from DotF, for example.
What if you cast dispel magic on a flying wizard and then as he's "gently floating to the ground" you cast it again? Now will he drop?
No - there's nothing to dispel.
-Hyp.