Only found out what it is last week! Can you believe it?! Thought it was just a normal plant!

First noticed some in the tree outside a friends house and was like...'what's that? Is that... Is that...*squint*...a nest?' Decided it was a nest and forgot about it, but then started seeing it every where, it's all over bushy park. And I have to say while I was starting to doubt whether the clusters were nests, It did give me that slightly uncomfortable feeling when you see pictures of something parasitic in nature. Though I don't think it is because apparently it doesn't damage the host.

Don't know much else about it really, haven't googled it yet, just asked around old skool stylee.