For someone (actor -um- & theme i-) to crawl into a confined space (loc ref -on) which requires crawling or crouching; as for a person to go into a cave, under a table, through dense foliage; for a fish or crab to go into a crack in a rock.
For someone (agent & inst) to crawl with someone or something (theme i-) held into a confined space, as described above.