Dog Ear Problems yucky :[?

my dog cant hear well and we checked his ear today and there was this black gummy stuff that smelled horrible. it might be cancer or something. please help me and tell me what it is. my dog is like 5-6 yrs in human and medium size er spaniel. and if u know what it is, please answer and tell me how i can cure it. the black stuff kept coming out and it smelled bad. also, what medicine will i have to buy so that he doesnt die :[ hes a dog thats kept outdoors too. please help save my dog :[