has anyone seen this before? ..

i'm attaching photos of a black elder with these little guys attached to its side .. i'm interested to find out what they are .. and what they might do .. if it's necessary to cut this elder back below where they are living .. any comments appreciated ..
thanks

 

These look like the fruiting bodies of some fungus, but not one that I know. If it is a fungus, it's likely that the elder is a lost cause; however, you could try cutting it down to a stub and hope that a new shoot comes up from the base or the roots. I don't think that it is grafted.

 

It could just be a harmless slime-mould that has climbed up the stem for a dispersal point.

If the elder leafs out normally in spring, it'll likely be OK.

 

Can you squish them like an egg?

 

Not sure about bluish sacs but the fuzzy bits in the first shot are like woolly apple aphid.