Did some Destro upgrades from the $10 Amazon War Machine parts.
Fist with wrist joint added and I modified the blast effect to fit on Destro's gauntlet. Hollowed it out first, used glue gun to add bulk to the flames where required. Painted the missiles red.
It just clips on solidly right over the original wrist missiles. Totally removable. Kinda a fun, easy project made possible by that sale that I think adds a lot to the Destro figure.