If my creature with deathtouch and 0 power blocks one of my opponent's creatures, does my opponent's creature die?

Question

Deathtouch means that "any creature dealt damage by another creature with deathtouch is destroyed", but what if that creature with deathtouch is 0/1? I suppose a better title would be 'does a creature with 0 power deal damage in combat?', but it seems like deathtouch is the most prominent case where this would come into play.

Answer 1

No. Deathtouch still requires that damage be dealt:

702.2b Any nonzero amount of combat damage assigned to a creature by a source with deathtouch is considered to be lethal damage, regardless of that creature’s toughness.

Here's the more general rule as well:

119.8. If a source would deal 0 damage, it does not deal damage at all. That means abilities that trigger on damage being dealt won’t trigger. It also means that replacement effects that would increase the damage dealt by that source, or would have that source deal that damage to a different object or player, have no event to replace, so they have no effect.

A corollary to all this is that a creature with deathtouch can only kill as many creature as it has points of damage to assign -- for instance, casting Lure on your 2/2 Acidic Slime doesn't let you wipe out your opponent's whole team, just two blockers.