Can a familiar cast Simulacrum?

Question

While working on backstory elements for a noble character, I was trying to come up with a way to conceptualize a ploy to usurp the noble using a simulacrum. The ingredients were surprisingly at the ready in a noble's mansion, but I was having trouble getting around the idea that the usurper would have to be in contact with the victim for the full 12 hours it would take to form the duplicate.

Then I remembered that the Find Familiar spell has the following aspect:

Finally, when you cast a spell with a range of touch, your familiar can deliver the spell as if it had cast the spell. Your familiar must be within 100 feet of you, and it must use its reaction to deliver the spell when you cast it. If the spell requires an attack roll, you use your attack modifier for the roll.

So, given that the spell is not limited by the duration but by the range, does this mean that one could have their spider familiar nest on a target for 12 hours, given they are kept within 100ft (like in a nobleman's home), and allow the master to cast Simulacrum discretely at long range?

Answer 1

You can probably cast Simulacrum using a familiar

Obviously, the familiar itself cannot cast a seventh level spell as it lacks the Spellcasting feature. You as a wizard can cast touch spells through your familiar just fine. However, Simulacrum is a bit special. It states

You shape an illusory duplicate of one beast or humanoid that is within range for the entire casting time of the spell.

And the material components are

snow or ice in quantities sufficient to make a life-size copy of the duplicated creature; some hair, fingernail clippings, or other piece of that creature's body placed inside the snow or ice; and powdered ruby worth 1,500 gp, sprinkled over the duplicate and consumed by the spell

All of which implies that you do not just need to touch the target, you have to stick around for 12 hours because you are building a snow-creature from the material components, which then is transformed into the target's likeness.

It is possible that a familiar such as an imp or quasit could form such a creature. Unfortunately you cannot deliver touch spells through such a familiar as a wizard. It is unlikely that any of the "standard" familiars afforded by the spell, such as a spider, would be able to form such a snow-effigy.

However, if you were building the effigy outside (i.e. someplace else within the 100 foot range), and would during that time be in "touch" range with your vicitm via your familiar, and also have their hair, nail clippings etc. around, I think it could work.

Action Costs

On possible stumbling stone is that the implication is you need to have the target around to see how they look like, when you are shaping the duplicate. This, you could not do through your familiar, because the spell says:

Additionally, as an action, you can see through your familiar's eyes

And the PHB under Longer Casting Times (p. 202) says

When you cast a spell with a casting time longer than a single action or reaction, you must spend your action each turn casting the spell

So you could not cast the spell and at the same time look through the eyes of your familiar as both cost your action. However, the requirement of seeing the target is not explicitly stated by the spell, and therefore not demanded by rules as written.

Talk with your DM. Maybe he or she is of the lenient kind and will rule it is sufficient you took a good look at your victim before your started, to allow this stratagem. I likely would.