I Heard You Like Amber...

Easily soloable at 120, done as Demon Hunter in tank spec.

0. Shift+click to track the achievement. Don't kill the boss until it turns white.
1. Engage boss, and just stand there. Don't attack him.
2. When the Ambers spawn, kill them all in one place. NOTE: When you are transformed into the creature, don't use abilities on the Ambers. They won't count. Just auto-attack 8 of them until they all die in the same place.
3. The achievement will turn white. Start attacking the boss. Only use ability #1 on cooldown.
4. A monstrosity will spawn. Kill it. Only use ability #1 on cooldown.
5. Back to boss. Auto-attack and ability #1 until dead.

This achievement cannot be solo'd. At 110 take a friend. Do not dps the boss in phase 1 until you have 8 pools overlapping. Click "track" on the achievement so it will alert you (by turning white) that the criteria are met. Then zerg the boss. When one of you is transformed, the other must DPS you down to about 20% until you can press button 4 to break free. Don't consume any amber when transformed.

I heard you like amber, so I put some Living Amber in your Burning Amber, so you can overlap with some sap.