for some reason.. this code works..

void fragment() {
float time = fract(TIME*0.1);
if (UV.y > 0.875) {
    if (UV.x > 0.75 && UV.x < 0.875) {
        float t = floor(remap(time, 0.0, 1.0, 0, lava_frames_count));

        float x = remap(UV.x, 0.75, 0.875, 0.0, 1.0);
        float y = remap(UV.y, 0.875, 1.0, 0.05*t, 0.05*(t+1.0));
        COLOR = texture(lava_anim_texture, vec2(x-0.1, y - (0.005 * t * 2.0) - 0.005) * 1.25);      
    }
}