<mobs>
    <zombie>
        <id>Zoombie</id>
        <pack-limit>2</pack-limit>
        <spawn-if>
            <light>0 to 15</light>
            <blocks-from-player>above 10</blocks-from-player>
            <blocks-from-spawn>above 23</blocks-from-spawn>
            <ground-is-solid/>
            <success-rate>100</success-rate>
        </spawn-if>
    </zombie>
</mobs>