D&D 5E Does a Beholder need to "see" you to use it rays on you?

[jasper]

Ok had this question come up last night. Pc with an active cloak of invisibility. So the pc has greater invisibility cast on himself.
Question does the Beholder have see the target to use a ray?
This is the first time anyone brought up. I have had monsters cast various spells on invisibile people. I don't remember if any were single target only. BUT the person who brought this up has made me an Eviler DM. I notice the legendary actions occur after another "Creatures" Turn. I generally been doing after a PC went. hahahahha.

 

[MGibster]

There's no reason the beholder can't use his ray blindly. Even if targeting a single character the beholder could still fire blindly.

 

[jayoungr]

If the eyebeams had attack rolls, they'd be made with disadvantage. But as it is, they have saving throws. The beholder isn't targeting people--it's sending rays to a particular spot, where a person may or may not be.

Also, unless the invisible PC takes the hide action, everyone still knows where he/she is; they just can't see the PC.

 

[FarBeyondC]

Ok had this question come up last night. Pc with an active cloak of invisibility. So the pc has greater invisibility cast on himself.
Question does the Beholder have see the target to use a ray?
This is the first time anyone brought up. I have had monsters cast various spells on invisibile people. I don't remember if any were single target only. BUT the person who brought this up has made me an Eviler DM. I notice the legendary actions occur after another "Creatures" Turn. I generally been doing after a PC went. hahahahha.

Technically speaking:

The Eye Rays action (for both Beholders and Death Tyrants) specifies it can only affect targets it can see.

Eye Rays. The beholder shoots three of the following magical eye rays at random (reroll duplicates), choosing one to three targets it can see within 120 feet of it:

Eye Rays. The death tyrant shoots three of the following magical eye rays at random (reroll duplicates), choosing one to three targets it can see within 120 feet of it:

So a Beholder / Death Tyrant does need to see you to target you with rays using that action.

The funny / evil thing is that, because the none of the rays themselves list requiring the beholder / death tyrant see you to target you, their legendary action eye ray technically does work on a creature the beholder / death tyrant cannot see.

For consistency's sake, I personally wouldn't use the legendary action eye ray on something that isn't a valid target for the normal action eye rays, but it's technically allowed as written.

 

[Harzel]

The funny / evil thing is that, because the none of the rays themselves list requiring the beholder / death tyrant see you to target you, their legendary action eye ray technically does work on a creature the beholder / death tyrant cannot see.

Nah. References in the Legendary Actions or other places like Multiattack are generally references to other top-level entries in the Actions section. This is a weird case, because the Eye Rays action specifies the use of three rays. However, if you use only the text specific to each ray, then you have no specification of the range. If you accept that "within 120 feet" should apply, then I see no reason that "it can see" doesn't.

 

[jayoungr]

I assume "that it can see" in this case is meant to establish that the rays have to follow line of sight--i.e., they can't shoot around corners and suchlike. But I grant that is a case of RAI, rather than RAW.