Properly speaking, Booming Blade's effect is not additional or extra damage as it doesn't add to a damage roll but instead is a distinct damage roll, seperate from any previous attack.
OP specified 18th level, so the weapon attack will do extra thunder damage.
Properly speaking, Booming Blade's effect is not additional or extra damage as it doesn't add to a damage roll but instead is a distinct damage roll, seperate from any previous attack.
OP specified 18th level, so the weapon attack will do extra thunder damage.
This extra damage is on a hit so it'd be part of the primary damage, but not the conditional damage on movement
OP specified 18th level, so the weapon attack will do extra thunder damage.
This extra damage is on a hit so it'd be part of the primary damage, but not the conditional damage on movement