# Can a warlock choose an upcast spell as a Mystic Arcanum? [duplicate]

Can a warlock choose an upcast spell as a Mystic Arcanum?

For example, say I have a warlock and want to be able to summon bheur hags using Conjure Fey. This is slightly problematic due to bheur hags being CR 7. Could I then take an upcast Conjure Fey as my 7th-level Mystic Arcanum?

## marked as duplicate by linksassin, V2Blast♦ dnd-5e StackExchange.ready(function() { if (StackExchange.options.isMobile) return; $('.dupe-hammer-message-hover:not(.hover-bound)').each(function() { var$hover = $(this).addClass('hover-bound'),$msg = $hover.siblings('.dupe-hammer-message');$hover.hover( function() { $hover.showInfoMessage('', { messageElement:$msg.clone().show(), transient: false, position: { my: 'bottom left', at: 'top center', offsetTop: -7 }, dismissable: false, relativeToBody: true }); }, function() { StackExchange.helpers.removeMessages(); } ); }); }); Aug 26 at 7:27

• – MikeQ Aug 25 at 21:39
• – V2Blast Aug 26 at 7:28

## You cannot do this

The Mystic Arcanum feature states:

Choose one Xth-level spell from the warlock spell list as this arcanum. You can cast your arcanum spell once without expending a spell slot. You must finish a long rest before you can do so again.

This requires to actually choose a spell of a certain level from your list, unfortunately the upcast version of a spell is not on your spell list and so cannot be chosen with this feature.

That said, houseruling this would likely not be game-breaking as most spells upcast to a given level are weaker than other spells of the same level.

• "Most spells upcast to a given level are weaker than other spells of the same level." Has this been conclusively demonstrated? – mdrichey Aug 25 at 21:26
• @mdrichey This is true because higher level spells give you entirely knew capabilities instead of just increasing the power of previous ones. Summoning spells are one of the more edge-cases for this metric though, I'll admit – Medix2 Aug 25 at 21:31
• @mdrichey Another proof of this is the existence of higher level spells. If upcast spells were better then nobody would ever get higher level spells – Medix2 Aug 25 at 22:52
• True, damaging spells are not worth upcasting, but they are generally bad choices anyway. I would argue however, that the best 6th level spell is an upcast Banishment. Single target save-or-suck spells (Hold Person, Blindness, etc) have a good chance of failing, so completely wasting your action and your slot. If you upcast them, the chance of a complete failure drastically decreases. – András Aug 26 at 5:34