She waits

The ground seemed too unstable, and Vivia feared any attempt at running would go poorly. Instead she braced herself, planting her feet in a wide stance as the mud rose below, slipping aside and getting shallower. The redheaded rogue soon realized her location was the center of the swell, and before she knew it she was being lifted above the mudflat on the earthen mound.

She tried to stay balanced, but it grew too fast, and before she knew it her feet slid in opposite directions. With a gasp, she was swiftly sat astride the swell as it suddenly emerged from the ground and began pushing forward beneath her, a slick, muddy hill come to life.

She placed her hands on the risen ground before her, the smooth clay-like surface sticky with the mud of the flat. Looking around, she saw it carried her slowly, the spot where it first rose now behind her. The earth still emerging from that spot gave her the impression of a large, muddy worm—and she was atop it.

Vivia wasn't that far from the ground—or, the flat ground—but as the earth-worm moved with her on its back she worried dropping from it would result in another messy landing, so she hesitated, bracing herself astride the moving mass of mud. Soon enough it slowed, and she was surprised to hear something.

“Who rides my flesh?”

The words echoed in her head, but she quickly realized it wasn't a voice. It wasn't a sound, exactly, but the words registered with her nonetheless. The earth came to a stop, and suddenly everything was stable again

“Explain yourself, creature-child.” demanded the voice-that-wasn't. Another chill struck Vivia, this one more visceral. She looked down at the thing she sat on and reconciled it with legends she'd heard long ago, coming to the conclusion that it had to be an elemental. An Earth Elemental.