Mystery Goo

The garden is SO happy to have all this rain this week! Everything is growing great...even the mystery goo. The goo was noticed a few days after planting the garden. It seems to be "growing" from the ends of some of the cut roots. My boys poked sticks at it and a nasty decomposing musty smell filled the air! YUCK! I have searched the internet as much as I could to find a clue of what this might be and how to get rid of it. It has now been 2 weeks since the sighting of the goo and after my visit today I've noticed it's changing. I seems to form a orange/yellow scab. If it is not harmful to the plants I will just let it run it course but if it prohibits the growth of things in the soil then I would like to know how to get rid of it and it's smell! Thanks for any input.