https://wowpedia.fandom.com/wiki/GUID

Using GUID information, you can get the exact time an NPC spawned. It doesn't matter if the NPC is dead or alive.

Example addon: NPC Time
https://www.curseforge.com/wow/addons/npctime

Usecase:

1. A world boss or mount drop NPC is dead when you arrive. Hover over to get exact spawn time information.
2. Sha of Anger - The dead one doesn't despawn until the new one spawns. Use dead Sha to glance spawn time information. Example: NPC Time Screenshot

Feature Request:

• Add usecase-examples as cyclic (expired) timers.
  OR
• Add usecase-examples as normal timer by adding a few seconds (customizable?) to account for time to kill.

Relevant Feature Request:

• Added option: Add customizable (per world boss?) delay to cyclic timers to account for time to kill.
• Functionality: Automatically configure added delay to cyclic timers by taking an average of combat duration with individual world bosses. AND / OR take an average yourself and add that as the default value.

This is interesting. Thanks for sharing. I don't have much time for development right now but will consider this for when I do.

Indeed this is a pretty good idea. No need to request for timers if the boss corpse is up. Also for Sha of Anger i made myself a weak aura that plays a horn sound when Sha starts spawning. How i did that? Often boss's corpse stays until it starts spawning again so the WA triggers once the boss corpse disappear. Sha's smoke spawn phase lasts 30sec.

This is the weak aura im using https://wago.io/wQr-d9_Zh

I was just about to make this issue when I noticed this ticket. This integration would be great!

I consider this low priority due to the fact that it introduces another heuristic. Sha and so on with unpredictable timers is not very nice, and I'm hesitant to add another layer on top of that.

To avoid confusion, the feature would have to be opt-in, and the timer would not be share-able.