What is this ?

LilyandPoppy.

I was doing a bit of pruning on my Euonymus and I have found three of these. At first look I thought they were wasp nests but now realise they're not.

BobTheGardener

They are galls, possibly crown gall:

http://www.plantsgalore.com/care/disease/Diseases-euonymus-gall.htm

LilyandPoppy.

Thanks @BobTheGardener, that looks very much like it 👍