Modifying this terrifying monster so that it's poison does damage but you also forget the spider exists. Just instantaneously forget the spider exists and cannot physically, visually, or even smell it's existence and memory of it is also wiped from your brain. You save at the end of each round, but are not made immune to the effects on a failed or successful save, and can be re-poisoned in this way. 

How insidious is this? Probably a party wipe! :D 

If I was going to do that, I would probably alter the part that if you make the con save you take no poison DMG, otherwise there is nothing stoping the monster from eating the whole planet.

i dont like this

assuming you can collect this creature's venom like any other creature,  how would y'all rule on its effects?  full damage and paralysis?

Quote from Trewill91 >>

assuming you can collect this creature's venom like any other creature,  how would y'all rule on its effects?  full damage and paralysis?

 That seems logical to me.  That seems to be how Wyvern Poison (Injury) work.

What about having Phase spiders just sat there looking at the poor wizard who uses Blink? Muhahaha

I have an Arachnomancer (homebrewed) rogue who has a Phase spider companion named Aranae <3 she's my baby baby

As a bonus action, the spider can magically shift from the Material Plane to the Ethereal Plane or vice versa. There is akin to the Blink ability. It does not draw opportunity attacks.

This is completely incorrect by the way. According the Gygax, they subdue prey and take them to the Ethereal Plane and those that are taken are never heard of again.

For extra flavor, they could have this as an Action: 

Ethereal Web (Recharge 5–6). Ranged Weapon Attack: +4 to hit, range 30/60 ft., one creature on the Ethereal Plane. Hit: The target is restrained by ethereal webbing. As an action, the restrained target can make a DC 12 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 10; hp 5; vulnerability to radiant damage; immunity to bludgeoning, poison, and psychic damage). 

The webbing exists only on the Ethereal Plane, so they can't use it against prey without carrying them away to the ethereal first. 

(Without this, it's a bit weird that they have Web Walker but no web?)

Maybe it can make webs, but not shoot them in combat. Like, the make webs/lairs in the ethereal plane I believe, but they are not used to shooting webs mid combat, since they rely on ambush tactics. They generally aren't at a range where they fire webs. They are either in melee, biting or in the ethereal plane. So it would use its web walker ability in the ethereal plane, without having a web attack. Of course, that doesn't mean you can't make a variant that does have this attack.

Quote from Arion_Night >>

Maybe it can make webs, but not shoot them in combat. Like, the make webs/lairs in the ethereal plane I believe, but they are not used to shooting webs mid combat, since they rely on ambush tactics. They generally aren't at a range where they fire webs. They are either in melee, biting or in the ethereal plane. So it would use its web walker ability in the ethereal plane, without having a web attack. Of course, that doesn't mean you can't make a variant that does have this attack.

I'm confused by phrasing here, I think: I was suggesting a variant of a normal Giant Spider web, that only applies in the Etherial plane... (other than web & ethereal jaunt, the stat blocks are identical) Webbing in D&D restricts movement & that's all it does. Why does Phase Spider have "web-walker" to relieve that penalty, if it doesn't produce web at all? It becomes a useless ability, still counted against their CR. Seems like either there should be a web ability somewhere, or web-walker should get swapped out for a minor trait it can actually benefit from?

Keeping their webs ethereal means they are more dangerous in the ethereal plane than the material; but giving them web _plus_ ethereal jaunt does seem OP for their CR, even if that web can only be used on their home turf... Even limiting the Ethereal Web attack to 5ft range still leaves the Phase Spider a big 1up over the Giant Spider; yet having _no_ webs leaves them deficient due to the wasted web-walker trait!  :/ 

Not sure I see a perfect adjustment to remedy the situation, offhand. What would be an apropos replacement for "web walker" in their stat block?

would it phase pcs on it

how big is it around about, like compare it to another animal please

Quote from XKFuture >>

how big is it around about, like compare it to another animal please

 It's a Large creature, so around the size of a cow.

These are evil! They can phase in and phase out at will. Ugh!

Funni Spider

Mine is Jerry.

Nice!!!!!!!!

it has web walking but no ability to make webbing?