It must have been Electro Calefaction (the one with double damage, if I remember). I think I used that way too often :) Now I understand the stacking mechanism. When I applied blind multiple times, they all showed up next to each other on the enemy, as two blind(1)'s not adding up as blind(2). And I expected the stacking mechanism to work like blind for two turns. My bad :) This makes perfect sense now. Thanks!