Dragon Ball Super's latest manga chapter has revealed the anticipated story of the calamity that befell the Planet Cereal - and how exactly that dark genocide is connected to the histories of Freeza and Goku. The new "Granolah the Survivor" arc has primed fans for a tragic tale (it's obvious from the name of the arc), and they expected Freeza and the Saiyans (including Goku's father Bardock) to be at the root of said tragedy. However, Dragon Ball Super Chapter 77 surprised and shocked fans with how particularly brutal the massacre on Planet Cereal actually was!
(Warning: Dragon Ball Super Chapter 77 SPOILERS Follow!)
The flashback to Freeza's attack (and ultimate genocide) of Planet Cereal is pretty extensive. The eradication of the Cerealians is methodical and brutal, as the Saiyan Great Apes go full Attack on Titan on the Cerealian people and their cities. However, in the middle of that slaughter, we find out there were a second set of victims: a colony of Namekians living on Planet Cereal.
The story from the only surviving Namekian on Cereal (Monaito) tells of how the Namekians and Cerealians actually lived in happy and peaceful co-existence, until the day Freeza's army arrived. Freeza's men made a point to gather the Namekians all together in a huddle (save for Monaito, who was hidden), then they circle around the frightened aliens and execute them in a merciless firing squad. The Namekians are left in a pile of smoking corpses, except for the elder, who hangs on just long enough to pass the two Cerealian Dragon Balls to Monaito.
Namekians dying is no new thing in Dragon Ball - even Namekians dying horribly seems commonplace after Dragon Ball Z and Dragon Ball Super both feature gruesome Namekian massacre scenes. That said, The murder of the Namekians on Planet Cereal is just so fast and rote that it feels worse than those other aforementioned kills. The visuals of charred and smoking bodies in a pile is one you don't often see in this series.
This Granolah Arc has revealed a whole new origin story for the Namekians in Dragon Ball canon. We now know Namekians aren't so much aliens as they are beings from a different realm or dimension. The largest community of Namekian refugees in Universe 7 settled on Namek; however, it's been revealed that there are other, smaller, Namekian tribes that settled in other places across the universe. Each of these tribes apparently has their own set of Dragon Balls (including the dual set on Planet Cereal) - a reveal that exponentially expands the scope of where the Dragon Ball franchise can go.