The bombardier beetle produces hydroquinoes and hydrogen peroxide in separate chambers in its abdomen. When threatened, it contracts its muscles, allowing the two chemicals to mix. This creates a chemical reaction that sprays out oxygen and a 100 degree spray that kills it foes.

​

Inspired by this, the bombardier beetle model has a grenade attached to its abdomen that is punctured by a motorised arm. 

​

This was kept in the final prototype of the Sectibot, which carries a bomb that allows it to mass murder entire mutant ant colonies.