Translation of "껍데기에" in English

‎껍데기에 구멍을 뚫어 ‎뱀처럼 독을 떨어뜨려서

and then drop venom in there, like a snake,

‎문어가 잡는 연체동물은 ‎사냥하기 꽤 수월하지만 ‎단단한 껍데기에 싸여 있습니다

All the mollusks she is capturing, they're quite easy to catch, but they've got these incredibly hard shells.