Some of you probably have seen this facing me but yeah here it is!
For heavy chars(Snake, Ganondorf) use chain down grab repeatedly till about 20%. Although I don't recommend using this for light chararcters(Marth, Kirby) if you still wanna try just use one down grab(as they can DI out of the first grab easily).
Then forward dash to Up Smash when they are able to DI away and proceed to up A them to hell =). For someone like Snake this combo brings them from 0% to around 70%.
Rock on!