Destro's private army.

In terms of the history of the toy line, at some point Cobra Commander and Destro reconciled and some of the IG forces were folded into Cobra, like Metal-Head and TARGATS.

In the vintage ARAH comics, they seem to die when Destro's Scottish castle is blown up and he sheds no tears over any of them, nor does he recruit any new staff or anything for when he takes the Silent Castle.

In the Dic cartoons, they were never a thing. Undertows, Annihilators and the briefly seen TARGATS were Cobra, along with Metal-Head...as were the Razorback and Dominators.