Our deck is over 20 years and has tiny stands of jelly fungus fruiting bodies in the knots of its railing after a heavy rain. I photographed on knot in late July just after they appeared
And then a day later. They expanded very rapidly.
The jelly dried up but after a heavy rain last Thursday they were back and even bigger. They have a blobby beauty.
This means that the deck railings are rotting...and will have to be replaced at some point. Fortunately, the other parts of the deck have no yellow blobs!