Monster rearing

I have an Elasmoth at 2 and 1/2 stars for many days. What can I do to nudge it to 3 stars so I can feed it the upgrade food?

You can start at 2.5 stars.

The same thing you did to get it to 2.5. Feed it food it likes and give the action it likes without collecting. Can take awhile

I have been feeding it for three weeks with no change on three characters.

Do you mean you can feed upgrade at 2.5 stars?

You can feed the upgrade item at 2.5 stars. Have you been waiting till you hit 3 stars all this time?

Also, if you are feeding the correct upgrade feed, it's supposed to be 100% upgrade rate for food items from HNMs/bosses. If you are not feeding it the upgrade food, then it's gonna be a long and painful road, and I've not heard of anyone getting an Elasmoth to evolve without feeding it Gabbrath Meat, but should only take 1x.

What have you been feeding it?

I have fed Gabbrath Meat on two consecutive days with no change. The monster shivers uncontrollably but does not upgrade. Elasmoth does not upgrade 100%!!!!

Nobody said that was 100%. Upgrade food from HNM/bosses refers to savory shanks and the like.

Tojil doesn't qualify as a boss? It is a delve boss!

But the third Gabbrath meat worked.

It took me 5 tries to upgrade mine using Gabbrath meat, and i waited until 3 stars too. It "shiverred uncontrollably" each time, but only on 5th time did mine evolve to a Skormoth. Yeah it can be annoying.

Elasmoth just transformed to Skormoth today. It's been more than a month! I don't see a pattern, except it takes a long time.

I fed her Gabbrath's meat twice early on and then a second time when she was at 3 stars.