How the once-ler met sans

The fight.

Caillou goes to the oncelers house but the Lorax stops him because he knows he'll probably hurt a tree in the process and said "Stop! Do not hurt the trees it will be a terrible mistake." He held his hand to his heart with a painful face but Caillou didn't listen he smiled and waved but kept walking with confidence to the oncelers. On arriving he shot down the door and interrupted a moment between sans and the onceler, "Caillou!? What are you doing here we needed privacy!" The onceler claimed "I'm here to paint your suit red" he said shooting him in the leg to keep him out of his way but not kill him sans turned to him with a heartbroken angry look in his eye as the battle begun. Megalovania started playing as sans used to his power to make it loud and distracting but little did he know Caillou had had practice and was prepared to murder, he took a couple shots and took out a knife and swung at sans