Complex sentence: J2 has the power to change from his normal teenaged form into a unstoppable brute who is very tall, standing about 7'0 to 7' 8, with nearly all of the powers of his father, the Juggernaut.
Split into simpler sentences: J2 has the power to change from his normal teenaged form into a unstoppable brute who is very tall, about 7'0 to 7' 8. With nearly all of the powers of his father, the Juggernaut.