Cleave + Hideous Blow

[Yogibear41]

If I drop an opponent while using the Hideous Blow invocation, does the invocation continue to apply eldritch blast damage to the free attack I get from Cleave?

[BowStreetRunner]

No. The effect of Hideous Blow only takes place once. It uses its own standard action to make a single melee attack and then triggers if that attack hits. That's it.

Eldritch Glaive, from Dragon Magic, can be used to make multiple iterative attacks as well as attacks of opportunity. This one would reasonably be able to be applied to cleave attacks, although it doesn't combine with weapon damage.