Guild Wars 2

How do I counter MB other than the obvious dodge/invul/block? Can I reflect/destroy it?

It’s unblockable, so you can’t reflect, block or destroy it. Dodge, evade, invulnerability works.

Dodge is your best bet. It takes .75s to channel with a pretty obvious animation, and it travels pretty slowly. If the Mesmer is using it point-blank from stealth, you’ll just have to time it and take a guess about when the Mesmer will start channeling (hint: Torch 4 and Decoy both give 3s of Stealth without PU, and FotM PU Mesmers probably don’t have enough patience to wait the full 6s before trying to burst you). Then either dodge or use an AoE knockback.

tobascodagama.2961:

Dodge is your best bet. It takes .75s to channel with a pretty obvious animation, and it travels pretty slowly. If the Mesmer is using it point-blank from stealth, you’ll just have to time it and take a guess about when the Mesmer will start channeling (hint: Torch 4 and Decoy both give 3s of Stealth without PU, and FotM PU Mesmers probably don’t have enough patience to wait the full 6s before trying to burst you). Then either dodge or use an AoE knockback.

This.

It’s painfully easy to tell when the mesmer is going to come in and burst if it’s a 1v1 scenario and they stealth from around 1200 range first. You can almost always assume the mesmer is running PU. It’s a good thing to detect the stealth skill being used, which you can by the following:

• The Prestige: mesmer goes invisible with a “poof” type effect and sound effect which has an initial sound effect followed by what sounds like a miniature version of chaos storm. This means 6s of stealth before burst.
• Decoy: Disappears with the same miniature chaos storm sound effect if they’re out of combat; if they’re still in combat from their prior engagement they disappear with a clone running away from the location they used the skill. Again 6 seconds stealth.
• Mass Invisibility: Their arm in the air for a couple seconds then invisible with a ripple effect. This means 10 seconds stealth.

I didn’t mention Veil because literally no one uses it in PvP.

Mass Invis can be the trickiest because almost always they won’t wait the full 10s to burst on you. It’s best to just find a piece of structure to LoS behind; kind around it. This makes it very difficult to land the burst. For prestige/decoy, the counting is very easy and you can just dodge the obvious incoming burst.

Even with that knowledge, as tobasco said you can see the blade just a split second before it hits you, even at point blank range giving you just enough time to dodge.