This is currently a limited time issue for Abathur where Devs brought back the broken Locust Bomb.

I added some effective alternatives to practice with for when it gets changed.

Locust Bomb can let you mine for vision then release locust brood behind a fort before hearthing. You can also fire off broods at camps and at temples. You can use mines and your mule to tank some cannon shots.

The Spike Burst is a super push forward build. You hop waves with your hat to burst fire and shield while collecting xp, before moving on, not staying too long at all. You can add mines to waves coming in or use them between waves to discourage rotation by enemies. The extra spike range plus slowing spikes and twin symbiote will let your teammates chase down or escape enemies.

Carapace can help push by shielding and planting mines, but can also provide vision and protection to teammates. Use your Monstrosity to guide your shields, and twin symbiote to extend the range. The movement speed buff will help your team chase down or escape enemies.

Monstrosity build empowers your Monstrosity and turns it into a 'Tank' for your stab 'Turret' shots and deal extra melee damage.