Has a right-click option "Drain" which deals up to 50 damage, as well as reducing a random combat skill.
Lasts 36 minutes.
Notes:
Made at a Summoning obelisk while having a green charm, 88 shards, a summoning pouch and a zamatrice egg in your inventory: gives 75.2 xp. Using it costs 5 summoning points and gives 0.9 xp.