I'm guessing it is not showing up in the in-game simulator because it is part of the current event, however that shouldn't prevent it from being breedable. It would be nice if there was feedback showing the dragon greyed out to indicate it is not currently breedable (if that's the case) instead of not appearing. I think this is an oversight where it does not account for event dragons correctly. You can report the bug by contacting their support email: dragonvale@decagames.com.

Alternatively you can try the on-wiki breeding simulator (in desktop mode only) here: https://dragonvale.fandom.com/wiki/Breeding_Rules

Honestly I think its just kinks that need to be worked out. I too put in some pairings and double checked to see if it would result in my wanted pairing and it wouldn't show up. So I checked the sandbox and it was so I trusted the sandbox and after a few tries I got it. So long story short trust the wiki and sandbox.

Even if i trust the sandbox and wiki, ive gotten no luck, ive used my apocalypse dragon "Colossus" and Spirit dragon "Ancient" but have gotten nothing except for commons or non-event rares

3 days of spam breeding in the Rift and got it on the 1st 15k try. Only one left for the day.

Sooo glad it was a traited version!

Congrats! According to the https://dragonvale.fandom.com/wiki/Breeding_Odds page, Charlatan has 1% if you already own one and 0.75% if using a single Charlatan as a parent in a non-coop cave. The odds are low, so sometimes it takes a while to breed one, but it is possible to be bred!

I am so glad it is just a bug in the pairings results page. Not sure why they are not pulling from the same list/table for actual results, but guess it's a programming thing.

Will this work with a ghostly spirit dragon?

Hi, if you're talking about cloning, then yes, Ghostly Spirit can be cloned in any cave at 10% if using a single parent.

Otherwise, since Ghostly Spirit is available in the current event, it is able to be bred using Ghostly Ghost Dragon and a Ghostly Spectre Dragon at any cave at 3% odds.