What to do when the succulents outgrown from the terrarium glass?

What to do when the succulents outgrown from the terrarium glass?

Do beheading and grow more babies from it! 

A few keynote during a beheading:
1. Make sure there're few nodes on the stem of succulent cuttings, those are the spots where roots will grow.
2. Use clean scissors to cut, and put aside the cuttings, let the wound dry up before planting into soil again. You may plant it in a new pot after the wound is calloused to get a new pot of succulent!
3. Water the terrarium following the original schedule, and have some patient for the new babies to come out from mother plant again! Slowly they will grow prettier and prettier with the proper growing condition.