Ali was telling us all that whilst he was able to cope with anything on 2 legs he wasn't as good with things that had 6 legs and instead he needed the help of "d-CON" to rid him of roaches (no, not Freddie!).
Ali not only did photograph style adverts (see the picture) but also featured in television adverts for the brand (see below thanks to commercialclassic).
Oddly whilst Big George and his grills are widely remembered not many really recall Ali's roach killing traps and sprays. Despite the forgotten link D-con do continue to market traps, though they've turned their deadly attention to mice. I assume they found out that roaches are indestructible (a bit like Ali's chin).
Note-there were at least 2 Ali adverts for "D-Con". The one below is for the spray whilst the other one is for the traps (that you can see in the picture above)