The only noun I know derived from the verb to entomb would be the noun entombment.
It is an abstract noun, which means that it doesn't have a physical shape - you cannot touch it or smell it, just like with love, or hate, or happiness. Entombment is the process of placing a dead body into a tomb, or a grave.
Fffffffffffffffffffffffaaaaaaaaaaaaaaaaaaaaaaaaaaaaallllllllllllllllllllllllllllllllllllssssssssssssssssssssssssssssssssssssssseeeeeeeeeeeeeeeeeeeeeeeeee
false God bless!!! *)
The tone should be serious/alarming but since the tone should also be happy.