Slimey Fungus?

We went to Hardwick Hall near Chesterfield today, and amongst other interesting things we saw was this growing on a rotting tree trunk.
Lycogala epidendrum, commonly known as wolf's milk, is an interesting species as it starts off as a single celled amoeba that spreads across the tree, and is classed as a slime. Some descriptions say it isn't a fungus, but others say it is.
Perhaps the most interesting thing is this fruiting body, which is quite striking.