Okay, who give Spike too much Rumble Ball fast, so he will cause the trouble at Ponyville on Secret of My Excess?!  
However, on Season 5, Spike has gained the ability to keep control of himself and communicate coherently while in this form which he named Dragon Power, though his voice is significantly deeper. It is now the only form he needs a Gem for and, by eating one, he can stay in it for three minutes. However, it still requires a colossal amount of energy to use; after reverting to normal, Spike is too exhausted to move for approximately 23 hours. And also, when Spike get his control of himself when he’s all grown up, you’ll look at Spike doing some random dancing thing like Chopper does this:  
What do you think?