Oatmeal is a Human food which the Animorphs once used as a weapon against the Yeerks. Instant maple and ginger oatmeal can keep a yeerk alive without the need to absorb Kandrona Rays every three days, but will drive them mad through addiction. Initially, the oatmeal was viewed by the Yeerks as a potential asset during times of Kandrona scarcity, such as that which occurred after the Animorphs destroyed the Earth-based Kandrona source on the top of the EGS tower. However, they later discovered that it drove Yeerks and their human hosts insane, and thus understood it to be a dangerous substance.
During a battle at the Yeerk Pool, the Animorphs managed to throw several barrels of instant maple and ginger oatmeal into the pool and use a Dracon beam to explode it, causing some yeerks to be infected and giving them a distraction which allowed them to escape. 
|Earth/Human Technology||EGS tower | Oatmeal | Battle Morph|
|Andalite technology||Andalite Disc | Dome Ship | Escafil Device | Hirac delest | Mirrorwave call | Z-space transponder | Morphing | Mag-Hover Truck | Quantum Virus | Shredder|
|Yeerk Technology||Anti-morphing ray | Dracon beam | Gleet Bio-Filter | Kandrona | Kandrona Rays | Nova-class Empire Ship | Pool ship | Blade ship | Mag-Lev Train | Hunter-Killer Robot | Yeerk Pool | Bug fighter|
|Ketran Technology||Explorer | Time Matrix | Fire-And-Forget Explosive Homer | Uninet | Adge|
|Other||Dropshaft | Ixcila(Arn) | Pemalite crystal | Skrit Na Saucer | Hawjabran Colony Ship | Hawjabran Freighter|