Good shampoo recommendation? ?

Can anyone recommend a good and bad shampoo for dogs that actually gets rid of awful smells? I’m not meaning general dog smell (quite like that!) but disgusting “why have I got a dog” smell!
Cecil has just found an indescribable bad thing. It was green and full of maggots. It was intense fun and “leave” went out the window!
He swung it merrily all over his body. ?
He’s just had a pretty bad introduction to bathing, poor dot!
I used some old dog shampoo, probably been there years. Baby powder smell (almost as bad as rotten innards)
He’s spent the past 10 minutes flinging his wet still smelly body at me til I gave in. He’s now curled up on my lap with bit of a shiver and emitting a stench of death and baby powder at me.
There has to be something really good (for future trauma)
I don’t care what it costs to save this.