Ok....we don't know of any way to do this, but let's assume we found a way for a second. Would you require something to give you a push before you began moving at c or would you just instantly acquire that velocity? In what direction would you begin moving? Must all zero-mass objects travel at c or can some travel slower, or be stationary? What if you were in an environment with no outside influences and you acquired zero mass? With nothing to push you, would you remain stationary? If you did, would you have zero energy?