Baby corn is young corn, usually eaten whole, yes, cob included. They are boiled, or tossed into stir-fry dishes. Cooking doesn’t change its texture – they are as crunchy and sweet as raw. They can be found fresh in Asian grocers or canned would be an acceptable substitute.
While fresh baby corn is incredibly delicious and snappy, they are difficult to find fresh. I use canned baby corn more for the texture and color than its taste (and they are fun to eat!)