These include hand stencils , dynamic figures in large head-dresses carrying spears and boomerangs , Namandi spirits and mythical figures , including Alkajko , a female spirit with four arms and horns . These include hand stencils , dynamic figures in large head-dresses carrying spears and boomerangs , representations of Namandi spirits and mythical figures , including Alkajko , a female spirit with four arms and horn-like protuberances .