It depends on who the beneficary was, as well as the terms of the Will. If the beneficiary was your child who had children his or her children will stand in your child’s shoes and receive what you left. This could be language in your Will or if not controled by state statue if not. This is referred to as “rights of representation”. If you provided in your Will who would receive the property witout representation there is no representation.
If the beneficiary is not one where representation applies, then that gift will fall under the residuary part of your Will.
Your Will could also state who receives in that situation such as where you provide ” A, B and C or the survivors”.