12 inches tall, 18 inches long if you measure to the end of its leg tip.
Here she is! [link]
That'll take you to her Etsy listing, but here is the short narrative from the listing:
"She was born and raised within the dark and dusty walls of an unimaginably beautiful, historic world overrun by countless pests and vermin. It was a terrifying sort of place; dangers throughout every hallowed hall but Gladys Pillburough isn't the easily terrified sort.
She was but one of thousand in her brood, but she was quick and more importantly she was clever. When she was small she'd kept to the swarms; there was strength in numbers. She and her brethren grew older and larger, leaving their nest and pushing forward into the perils of the unknown.
She observed and studied the lesser ones; those that scurried mindlessly or meandered without caution. She scurried past the larger beasts and gobbled up the smaller pests. She quickly learnt to avoid the web filled corners which too often made easy meals for those endlessly patient predators hidden in the darkest shadows.
She was a survivor. Moving swiftly in the daylight, leaping across the treacherous landscape, growing stronger and quicker with each passing day. She outlived all her siblings and mothered a great deal of children. A matriarch who dwarfed even her greatest potential foes. Whether they possessed claws, fangs or wings, none could truly oppose her.
However, Gladys Pillburough had yet to face her greatest challenge. A new era of terror would soon be upon them all. Monstrous creatures who spoke in thunderous booms. They were bringers of light but they would seek the absolute devastation of her sacred home. She would protect all those who dwelled here. She would become legend!"