Its like Reeces peanut butter cups: "Two good things that go great together." With Megabolt Megatron just out and Fortress Maximus coming out in September you'll be able to combine these two figures to make your very own Robots in Disguise Megabolt Maximus!
Megabolt Megatron mounted on the Fortress Maximus body.
We are not sure if this combination was intentional, but there definitely is a very simple and effective way to merge the head of Megatron with the body of Fort Max. Just remove Max's head and snap in Megatron's in its place and you'll have a mighty Mega Max ready to take on anyone.

Close up of how and where Megabolt attaches to Fort Max.