Eldritch Claw
You learn the primal savagery cantrip. When you cast this cantrip, it deals bonus damage equal to your warlock level + your Charisma modifier.
Thoughts
This was just a simple desire to provide a melee option, for warlocks which would rival Agonizing Blast.
This invocation creates an option that deals a bit more damage than Agonizing Blast At most it wins by ~5 points, which I see as acceptable since it is no longer ranged, and does not benefit from Hex or similar as well as Eldritch Blast does.
Lingering Savagery
You learn the primal savagery cantrip. When you hit a creature with primal savagery the target must succeed on a Constitution saving throw versus your spell DC. On a fail you leave a lingering acid burning them. At the beginning of each of the creatures turns for the next minute, they take 1d4 + your Proficiency bonus acid damage.
The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
The damage increases at 5th, 11th and 17th level by 1d4.
Eldritch Savagery
You learn the primal savagery cantrip. When you use your action to cast this cantrip, you can use your bonus action to cast the cantrip again.
Thoughts
These were two different options, to provide some more interesting ways to boost this cantrip. Eldritch Savagery stays a bit ahead of EB at all levels.
Lingering Savagery is a bit ahead as well.
Notes
All of these invocations are not supposed to be allowed together, only a single invocation is supposed to exist in a game.
I am aware that all of these are brilliant for dipping, and that is not by mistake. Agonizing Blast and Eldritch Blast are just as good for dipping which is why I decided to leave these as this as well.