I recently stumbled upon a video dating from March demonstrating rotting fruits using morph targets, which I find really impressive.
The description mentions that the example “comes with the engine”, however I haven’t found a single trace of it.
Does this example project still (or even) exist somewhere I might be able to grab it?
This was asked before and the answer was it isn’t ready yet and will be released sometime in the future. It looks beautiful but it is very simple if you are insterested in how it was achieved really, the whole thing is Matinee driven. The only complication is the assets, which depends on your artistic abilities. 
I’ve reached out to see if there is any plans to release this content in the future, so I’ll let you know when I find out.
This was content that was included for those who were using the Unreal Engine Beta.
The entire scene, as Jacky pointed out, is using matinee to drive morph target animations. These animations which we do have an example of morph targets in our Content Examples project from Marketplace > Open Map > MorphTargets.umap
I opened the project and took a look at the assets. They are not overly complicated assets. They have been morphed in a modeling program. The materials are a base a material with an instanced version to handle the darkened rotting color.
Tim
If you check the road map vertex based animations is included in the animation section. Be sure to up vote it. 
it can do this and a lot more with out having to do any fancy morphing.
Thank you for the replies! Looks like I wasn’t being throrough enough in my forum search.
: Being familiar with morph targets, I was wondering if any additional effects or animations were used to produce this effect. If it takes only a morph target animation and a transition between two materials to achieve this effect, that’s really impressive! Allbeit these are really well realised models and materials.
: Thanks, I’ll give it a look!
Everything you’re seeing in the video is fairly straight forward.
There is nothing special about the meshes aside from making sure they have enough verts for their deformations. (All this is setup through your modeling software for the animation).
It’s then brought into UE4 and the morph target animation will loop, which is what you’ll see in the video below.
Each mesh only has one material applied that is a dynamic instance of the base material.
The dynamic materials and the animation are all being driven through matinee for the change.
Hope this helps! 
Tim
Here’s a quick vid of a few of the fruits just looping their morph target animations.](Dropbox - Error): Sorry for the sub-par quality. 
In addition to Tim’s explanations, there is also Set Morph Target node in blueprints for skeletal meshes which could let you do the same animation without Matinee.
Here’s something i had made during beta(set with Matinee.) The slight jump in transitions is caused by my noobishness while creating morphs. 
That pottery looks really good!
Thank you for the explanations, they cleared a few things up! I’ll be messing around with morph targets a bit I reckon.