Here are some examples:
* The diamond was encased in a thick layer of glass. (meaning the diamond was protected by the glass)
* The ancient artifacts were encased in a glass display case. (meaning the artifacts were enclosed for preservation and viewing)
* He felt encased in a thick fog, unable to see where he was going. (meaning he felt confined and lost)
The word "encased" implies that whatever is being encased is completely surrounded and often incapable of escaping or being accessed easily.