I just used a Minor Heal on an enemy in order to trigger and eliminate its block card. The enemy was at full health; one move later, it's dead.
Just for those wanting to use this, it won't work if there are no allies in range unless you turn off the autoselect option.
Oh, it was essential to turn off autoselect. For those who don't know, hold the control key (or equivalent on Mac) when clicking your card.
Like I said: enemy at full health to start. That's when I'd cast Bad Medicine on an enemy, too, but I didn't have one drawn.
You know, I went "Yes!' when I used that above technique. Now I've gone "Yes!" again. This time, my Priest had Unholy Frenzy available. A goblin had one health. I figured there was nothing to lose, so I cast it on the goblin: hey, I'd killed enemies (imps) this way before. But what happened was that the goblin's Reflect Missile card succeeded and applied the Frenzy card to my Priest. The goblins thereby made their problem worse: melee gets through more of their blocks than magic does. Or, in brief, I used a "non-self-targetable" card on my Priest's "self." HAH.