When you're super over-levelled for a world that has an alert/ unfinished quest.

Build loop:
1. Blow whistle
2. Allow packs to hit you
3. Packs take Cactus damage and chain explode
(4. Use singularity to reduce whistle cooldown on elite monsters
5. Use boombox to finish stragglers)
6. Repeat

You heal from both, Whistle and Pendant.
Can substitute Boombox for SnowGlobe, but longer CD + lack of stun for niche situtations makes it relatively slower.

Free feel to drop any questions and I'll do my best to answer them!