This is a rather devious card combo that my friend used against me in
my starting days of magic that left me sitting helpless.  In case you're not
familiar with the cards, they are both from the Mercadian Masques card set.  
Dehydration is a blue enchant creature, which makes it so that the enchanted
creature cannot untap during it's untap step.  (Keep in mind, you must make
sure the target creature is already tapped.) Insubordination is a black
enchant creature, which inflicts a large amount of damage over a short
period, as it deals 2 damage to enchanted creature's controller every turn
unless that creature attacked this turn.  Example:  I was playing a hollow
dogs, a 3/3 black creature which gets +2/+0 when it attacks.  I think it was
probably the biggest creature in my deck at the time.  My friend used the
combo, and not only stalled my Hollow Dogs, but inflicted 2 damage a turn to
me on top of what his creatures did.  You can substitute Dehydration with
Manacles of Decay, Pacifism, or Shackles if you play white, but you can
probably find other cards that match the cards effect in some other color.  
This combo is a subtle killer, which can only be stopped through
counterspell-type-things, or disenchant-type-things.  Hope this combo works
for you!

                                          -JD Wolk,