this is undertail. I don't know how to code this property so if I make any mistakes please tell me

You struck him down, watching as Sans collapsed in a heap, the fight seemingly finished. But as you began to walk away, a chilling sensation crept up your spine. The air hummed with a strange, pulsating energy, and a low, distorted laugh echoed through the space. Sans rose again, but he was different—his body shimmered with an ethereal glow, and his eyes were alight with a power that felt ancient and unstoppable. His final form was a terrifying spectacle, a testament to the indomitable spirit that refused to stay down. The battle was just beginning, and the true Sans was ready to unleash his full might.

‘Beneath the shimmering full moon, the demon cat stands as a living shadow on the snow. Its fur, a tapestry of midnight black and ghostly white, ripples with an otherworldly aura. The stars above seem to quiver in its presence, as if acknowledging the wrath contained within its form. You watch, transfixed, as it turns its gaze upon you—a gaze that holds the weight of a thousand storms. The air crackles with tension, warning you that to approach is to court disaster. This is no ordinary feline; it is a creature of ancient fury, a demon cat whose very existence is a testament to the power of untamed rage.’