As I can tell, Simmer was eventually defeated with the power of love-hugs and the town went on its merry way to clean up. He/It became a foal known as Garion and followed Foxglove et al to the Greenhouse thread.
Icy ended up dragging Sandy to the library for Science!(tm) while Gear and Silverpine followed them inside. Together with Flower Tail and Winterflap, they all got into a big scrap/argument about the science before Sandy snapped and yelled for all of them to stop. I think now we're dealing with the aftermath + other stuff.