Indestructible and Yahenni's Expertise

[Silver]

The opponent had Selfless Spirit and 2x Makindi Aeronaut out, as well as 1x Always Watching. This made the aeronauts 2/4 instead of 1/3 and the Selfless Spirit 3/2 instead of 2/1.

I attacked with my lone 2/3 Stitched Mangler, baiting him into blocking it with one of his Aeronauts. He did, and the Aeronaut was at 2/2 at this point.

I then cast Yahenni's Expertise, in response he sacced Selfless spirit to give his two Makendi Aeronauts indestructible.

Yahenni's Expertise reduced both the Aeronauts' toughness by 3, and yet BOTH survived (incl the one whose toughness had been reduced from 2 to -1) instead of just the other one with T4 surviving.

How is this possible? I thought "indestructible" only protects from "destroy target" or "destroy all" spells, and will not keep your creature alive if its toughness gets reduced to 0 or less???

[Protectron]

Don't be fooled by the Duels graphic. The Aeronauts were still 2/4 (-3/-3, so after Expertise: -2/1), and one other thing Indestructible does is to prevent the creatures from being killed from lethal damage.

Duels shows that Toughness is reduced when damage has been dealt, but this isn't what happens. The graphics should show the Toughness still being 1 and a red 2 next to it showing how much damage it was dealt.

[Silver]

Just for the record: the creatures gained indestructible AFTER the combat phase was over.

But, I see. So if you deal non-lethal damage to a creature (e.g. a 4/4 blocks a 2/2 and is dealt 2 combat damage this way), if you then cast a spell that gives that creature -2/-2 until end of turn, it will not die, correct?

[Protectron]

if it has Indestructible, correct.

If not, it dies.

Damage lasts until end of turn.

[Pembroke]

Originally posted by Silver:

So if you deal non-lethal damage to a creature (e.g. a 4/4 blocks a 2/2 and is dealt 2 combat damage this way), if you then cast a spell that gives that creature -2/-2 until end of turn

Before the spell it's a 4/4 with 2 damage counters. After getting indestructible it's a 4/4 with 2 damage counters and indestructible. After the spell it's a 2/2 with 2 damage counters and indestructible and the indestructible prevents the 2 damage counters from killing it.

If you had cast a spell that dealt -4/-4 instead it would have died because then it would have been a 0/0 with 2 damage counters and indestructible and indestructible won't prevent the removal of a zero toughness creature from the battlefield.

This isn't Duels specific. Paper works the same way. The Duels specific is that it shows you the "net toughness" as the toughness instead of damage counters which is usually the more convenient way to see the state of the creature but it does hide things when you have indestructible or similar abilities applying...