<spawns>
    <outcome affected_mobs="creeper">
      <conditions>
      </conditions>
      <actions>
        <set_powered_no/>
        <set_title>§cCreeper §7Lvl 1</set_title>
      </actions>
      <actions ratio="2">
        <set_powered_no/>
        <set_skin>Your URL here</set_skin>
        <set_title>§cCreeper §7Lvl 3</set_title>
      </actions>
      <actions ratio="2">
        <set_powered_no/>
        <set_skin>Your URL here</set_skin>
        <set_title>§cCreeper §7Lvl 13</set_title>
      </actions>
      <actions ratio="2">
        <set_powered_no/>
        <set_skin>Your URL here</set_skin>
        <set_title>§cCreeper §7Lvl 17</set_title>
      </actions>
      <actions ratio="2">
        <set_powered_yes/>
        <set_skin>Your URL here</set_skin>
        <set_title>§cSuper Creeper §7Lvl 26</set_title>
      </actions>
      <actions ratio="2">
        <set_powered_no/>
        <set_skin>Your URL here</set_skin>
        <set_title>§cDoom Creeper §7Lvl 27</set_title>
      </actions>
      <actions ratio="2">
        <set_powered_no/>
        <set_skin>Your URL here</set_skin>
        <set_title>§cDead Head §7Lvl 27</set_title>
      </actions>
    </outcome>
  </spawns>