Kiss of Mephistopheles eldritch invocation allows you to get Fireball 3 levels early, by casting it after eldritch blast hits as a bonus action, which means at second level, you can

end up doing 1d10 + 8d6, with your leftover invocation, you can get Agonizing Blast invocation, lets say its just +3 because that seems average.

For the average of a 1d10, 6. A 1d6 is 4 average, so 6 + 32 + 3 = 41 damage

Yowza.

Level 17 warlock with 20 cha, agonizing blast, and illusionist bracers: 1d10+5 per ray, 8 rays, 84 damage. Per turn. An unlimited number of times. Hmmm…

But with a cha casting stat. For wizards, that’s not great

Is that homebrew?

 This is pretty damn powerful 

Maybe there’s an eldritch being that towers 600 feet tall

cum

Does the blast have to emenate from the hand? Could it come from a charcter's foot? This is assuming that the character has a hand free for the somatic component. 

although its a cantrip level spell, its still quite powerful...

Quote from Gadigan_Thunderguild >>

Why is this spell so good, its just 1d10 damage? (asked previously; let me add to the answers in an attempt at clarity)

There are some other aspects of the spell, beyond raw 1d10 damage, which can make it slightly better than other options / comparable spells. And people get excited over these slight differences. Though some of the difference is people's preference based on common situations (so individual preference may vary). Compare Eldritch Blast to Fire Bolt

• Users
  • Fire Bolt - wizards, sorcerers, artificers, even eldritch knights (fighter sub-class)
  • Eldritch Blast - Warlocks only - advantage eldritch blast because rarer is cooler :-)
• Damage
  • Fire Bolt - 1d10 fire damage, can target objects; so you can set curtains on fire from across a room, but some monsters resist or are immune to fire, like fire giants (immune). Of course some may be vulnerable to fire (though not frost giants or white dragons so I stopped looking).
  • Eldritch Blast - 1d10 force damage, creatures only; so you cannot damage say a locked door (rules as written), but few monsters resist (or a vulnerable) to force damage.
    • advantage eldritch blast as most people prefer reliable damage (1d10) over running into monsters that resist (or are immune) to fire bolt damage, or over the ability to damage flammable objects at range.
  • Damage Bonus
    • Fire Bolt - no
    • Eldritch Blast - no - but, warlocks have the eldritch invocation class feature one of which is agonizing blast which a lot of warlocks take, allowing them to add their CHA modifier to the damage roll
      • advantage eldritch blast. Not every warlock takes the agonizing blast invocation but enough do that it becomes noticeable that fire bolt does not have the damage bonus.
      • You may notice people disliking warlocks, or eldritch blast with agonizing blast, as it takes the seeming flexibility of the class (what spells and invocations you want to choose) but restricts it to one optimal choice. Saying that 'all' warlocks are eldritch blast warlocks is like saying that 'all' sorcerers just cast fireballs. Yes there are other ways to play but there is also an obvious, simple, effective choice.
  • Flexibility
    • Fie Bolt - None
    • Eldritch Blast - other eldritch invocations can make other changes to eldritch blast. Like extend the range of the spell, which is normally 120ft for each, or push targets up to 10 ft. Not big differences but still some flexibility that may be useful in certain scenarios and which some players may find fun or find ways to use effectively often enough to make Eldritch Blast 'better' than Fire Bolt. For example knocking an escaping enemy that thought they were a safe distance away off of their flying carpet to fall to their death.
  • Higher Levels
    • At higher levels (5, 11 & 17) both cantrips can do more damage.
      • Fire Bolt-"This spell's damage increases by 1d10 when you reach 5th level (2d10), 11th level (3d10), and 17th level (4d10)." It is still a single bolt of fire attacking a single creature/target. One bad attack roll and you miss.
      • Eldritch Blast - "The spell creates more than one beam when you reach higher levels: two beams at 5th level, three beams at 11th level, and four beams at 17th level. You can direct the beams at the same target or at different ones. Make a separate attack roll for each beam."
        • The raw damage is equivalent. At 11th level the three eldritch blasts do 3 x 1d10 damage.
        • But at 11th level with agonizing blast you also add your CHA modifier to each hit so (assuming +4 CHA bonus, and all beams hit) actual damage is (3x1d10)+(3x4). Basically the eldritch blast+agonizing blast warlock is doing +12 damage compared to a wizard of the same level and equivalent spell. The wizard will not be doing warlock level 11 damage until level 17 when they get their 4th d10 of fire bolt damage. And at level 11 the agonizing blast warlock is doing an extra 12 damage while at level 17 the fire bolt wizard is only doing somewhere between 1 - 10 more damage. So more damage, and more reliable damage (damage bonus rather than rolling a damage dice).
        • More flexibility, as you can target multiple targets if you choose.
        • If targeting a single target repeatedly each bolt is an independent attack roll so more chance that at least one might hit. Against harder to hit targets this can be more useful than the occasional miss against easy to hit targets. (Even better with agonizing blast.) And, again, people prefer the consistency of having some attacks hit over the all-or-nothing of Fire Bolt.

So it is not that this cantrip is super-good but, on average or in average play, it is noticeably better than the equivalent spell.

 
Bang on, awesome description. 

And then Hex is just icing on the cake. If you take this as your Level 1 spell with the Magic Initiate feat (or you’re a Warlock and just get it by default), spending your bonus action to pile 1d6 necrotic damage on every single beam is a bit of a no brainer.

Theoretically you could also pair hex with another cantrip, but they’ll never hit their target more than once… a bonus 1d6 vs potential 4d6 isn’t a very hard decision. 

The only reason you choose warlock is to cast everyone's favorite cantrip, Eldritch *BLAST*

Good countermove against Mirror Image.
Quicken spell for double the fun
Your character becomes broken if you ever get Illusionist's Bracers

Twinned Spell actually wouldn’t work with Eldritch Blast because Eldritch Blast can hit multiple targets. But Quickened Spell absolutely would.

Damn. That’s good. 

If you make contract with supernatural being, you can shoot heavy crossbow bolt dealing force damage with your finger.

You can’t twin an attack that hits multiple targets. 

If you get sorcerer meta magic distant spell then u can get 1200

Quote from ZeusTheGreat173 >>

Quote from CandlekeeperofCastle >>

If you're a warlock and don't get this spell, you should just eat your character sheet.

 That's true.

 Agreed, I always get it. It's easy to reskin too, one of my characters, Vapor (Fathomless warlock water genasi pirate) uses it and shoots blasts of magical glowing extremely blue water

 i think that would only work if you were aiming at one creature not a bad idea though

does the damage go up from 1d10, or do you need invocations?