Luffy Gear 4 Episode -

It wasn't a desperate heave. It was a slow, deliberate shift . A low, guttural growl echoed, not from Luffy’s throat, but from the earth itself. Luffy knelt on one knee, his head bowed. His body was steam, his skin a deep, angry crimson. He wasn't panting. He was breathing . Each inhale was a cyclone; each exhale, a furnace blast.

"Gear... Fourth."

He didn't launch himself at Doflamingo. He simply vanished . A sonic boom cracked the air a second after he reappeared—directly above the Warlord, his shadow eclipsing the sun. luffy gear 4 episode

"Don't get up, Mingo. Because next time... I'm aiming for the sea floor." It wasn't a desperate heave