Giant caterpillars

Giant caterpillars live on the banks of the Fiery River. They used to be harmless creatures. They do not need meat - they feed exclusively on lava - and therefore both people and animals could approach them without fear. But then something happened, and the giants started killing everyone indiscriminately. The surroundings of the river have died out... My guards managed to defeat several giants, but they couldn't cope with all of them. If you have time, please help us!