Complex sentence: When the Surfer rebuffs him, Doom attacks and the Surfer retaliate by blasting Doom through the ice, but the cosmic energy of the Surfer's blast heals Doom's body.
Split into simpler sentences: When the Surfer rebuffs him, Doom attacks. The Surfer retaliates, blasting Doom through the ice, but the cosmic energy of the Surfer's blast heals Doom's body.