What Could Be The Reason For Having Vomiting, Foul Smell And A Bowel Movement With Lot Of Mucus?

My son Vomited several Times this morning. He was feeling ill so he goes to rest. As he is sleeping getting some rest, I check on him every now & then. The last time I came in, it was a foul smell like a dead smell. I'm looking around wondering what May have cause this Horrible smell. I check my son to if he had passed gas or an accident. He says no. But as I get closer to him the smell gets even worse. I find that he had a bowl movement. But it was clear with a lot of mucous, I have never seen this in any of all 3 of my children, any kid I know. Please let me know,Very curious to know if I should seek some medical care.

Thank you