Giant scarab

The Giant Scarab is fought during the final battle of the Contact! quest. It summons level 68 Locust riders and Scarab mages to aid it in its battle. The Giant Scarab is the sixth highest level quest only monster that is fought via conventional means in the game.

It hits upwards of 20 damage with melee and ranged and is very poisonous, with the damage starting at 9 per hit. If you are out of Melee range from the Giant Scarab and are using Protect from Missiles, the Giant Scarab will "clack its jaws," and you will be poisoned anyway, unless you drink antipoison.

The grey object in its back is Kaleef's Keris dagger.

Combat strategy
Only the most durable should engage this monster in melee combat, players should bring an anti-poison, prayer pot, lightsource and tinderbox, weapon and armour you would not care about losing, good food and an Emergency teleport is vital. The Giant Scarab has extremely high defence against slash attacks and is immune to poison so the Dragon Dagger p++ and abyssal whip are not recommended.

The scarab is extremely weak to Iban blast, ice rush(or any other ice attack), and slayer dart and there is a safe spot in the south-west corner of the room that can be used for protection from his melee attacks as well as the spear wielding Locust riders. The official quest guide states that the scarab is weak to stab attacks. While hiding here and using protect from ranged, players can defeat the scarab while taking minimal damage from the mages.

Another way is to wait just inside the tunnels until the Scarab positions itself behind a water puddle and mage it from a distance with the appropriate protection prayer. Using this method, the scarab will NOT summon locust riders. Alternatively, if the Giant Scarab will not move, it may be possible to range/mage it from as far away as possible without it summoning any help.

It may also be useful to bring a combat familiar to the fight, since the area is multi-combat.