It looks like a dozen ants are sticking together in the ball, but they are all dead ants. And below that, there are insects that pull and drag the corpse like a small rucksack. It is the genus Acanthaspis petax (probably not in Japanese) found in East Africa and Malaysia. Like other hitmen, he hunts for prey by piercing and injecting saliva, but saliva causes paralysis, enzymes dissolve tissue, and then aspirate internal organs.
The characteristic of this insect is that it is used as protective clothing by using the carcass after eating food. The insect can carry as many as 20 dead ants at a time, solidifying larger masses with sticky excrement.
It hunts various types of prey such as cockroaches and flies, but it seems that only dead ants are piled up on its back. Some scientists believe that ant corpses can provide a mimicry of the sense of smell when hunting, while others believe that ant mountains can confuse larger predators. I think it can be used as a mimicry.