Damn those things are hard to kill.
Split your army. Have good amount of different kind of units around him and through anything you have. I remember playing a 2v2 and I was battling all myself alone against two scarabs. I killed them easyly with my big army of Hornets, Cyclops, Tanks and marines. The key it is to make the scarab to turn around, those things move really really slow, and keep away from the legs. Use you leader abilities to attack him and support your units.
I don’t know about you, but I use pesticide.
> 2533274807340992;3:
> I don’t know about you, but I use pesticide.
hahahahahaha
Grizzlies.
Scorpions.
Cyclops.
Hunters.
Wraiths probably.
Hornets probably
Banshees probably.
Split army.
Nightingale smoke screens work wonder.
i have killed 2 in a row and then was a server disconnect 
Everything melts them if you keep moving.
cyclops received one debuff its very hard kill scarab now.
“We’ve all run the simulations, they’re tough, but they ain’t invincible. Stay with the Master Chief, he’ll know what to do.”
Literally anything moving kills them
> 2535406820576751;1:
> Damn those things are hard to kill.
Not in my experience. Spam Cyclopses or upgraded air does the trick just fine for me.
> 2533274807340992;6:
> Nightingale smoke screens work wonder.
Exactly! Get multiple, and keep shrouding until it despawns!
Leather Necks… A whole slew of leather necks!
well hunters melt them… and if they dont have engineer backup then you can just cloak and pick them off.
> 2533274867382575;10:
> “We’ve all run the simulations, they’re tough, but they ain’t invincible. Stay with the Master Chief, he’ll know what to do.”
“Tank beats EVERYTHING!”
Cyclops work wonders on them
> 2533274818737568;16:
> > 2533274867382575;10:
> > “We’ve all run the simulations, they’re tough, but they ain’t invincible. Stay with the Master Chief, he’ll know what to do.”
>
> “Tank beats EVERYTHING!”
“Mother-! We can get past it sir!”
“Not without help.”
“But sir, you don’t have the firepower!”
“I’ve got the mass.”
> 2535405380102010;18:
> > 2533274818737568;16:
> > > 2533274867382575;10:
> > > “We’ve all run the simulations, they’re tough, but they ain’t invincible. Stay with the Master Chief, he’ll know what to do.”
> >
> > “Tank beats EVERYTHING!”
>
> “Mother-! We can get past it sir!”
> “Not without help.”
> “But sir, you don’t have the firepower!”
> “I’ve got the mass.”
If only he had the combat (Halo 4) Pelican…
Cyclops walk through them