The ability of a creature to deal combat damage after it is tapped or sacrificed should not be allowed. The confusion and rules lawyering aside it clearly a non-intuitive result. This problem is solved by a simple clarification of combat steps. 1) Combat phase is announced, responses made and resolved, 2) Attackers are assigned, responses made and resolved 3) Defenders assigned, responses made and resolved 4) Damage is assigned, responses made and resolved, damage is dealt. If you need a rationale for this think of it this way. I send over my Ogre (assign attacker), you Bolt him and I Giant Growth him (responses made and resolved), you throw an Elf in his way (assign blockers) we both pass (no responses), My Ogre raises it's club over your Elf's head as the Elf thrusts his dagger forward (assign damage) but you decide to use the Elf for mana at the last moment so the dagger never reaches it's mark (response and resolve) however the Ogre continues his bash and splats the Elf (damage dealt). This simplification of the combat phase would clear up most (if not all) confusion on damage dealing and cut out the rules lawyering caused by complicated response-resolution steps. Look forward to your input...the Limner.