Fungus or nest?

Fungus or nest?

Observation - Fungus or nest? - UK and Ireland. Description: This appeared this morning attached to the wooden sides of our raised pond (the outside, not near the water). At first glance I thought it was fungal but once I uploaded the photo I thought maybe eggs. The blob is about the size of a dessert spoon. Thi

This appeared this morning attached to the wooden sides of our raised pond (the outside, not near the water). At first glance I thought it was fungal but once I uploaded the photo I thought maybe eggs. The blob is about the size of a dessert spoon. This afternoon when I checked it the surface is now smooth, encased maybe? I'm wondering if it is a spider's nest but if so it's the largest I've ever seen!
EDITED TO INCLUDED PHOTO3 25/5/13 - it has now split to reveal brown powder which I guess is spores.