This thing is amazing. One of my characters got a staff of swarming insects, so he now carries spiders around with him, and they kick butt.

 Does Giant Spider have normal sight? If yes what does blindsight mean? That creature cannot be surprised by somebody sneaking around? 

Yes. A giant spider has 60ft of darkvision so it sees normally. Blindsense is designed to detect things without sight, like echolocation, so creatures cannot get closer than its 10ft range before automatically being noticed (even if invisible or silent). 

Just want to point out that this webby boy is the same size class as an ogre...

Web actions says "The target is restrained by webbing" so can the target be huge creature or larger?

Quote from HyperKoule >>

 Does Giant Spider have normal sight? If yes what does blindsight mean? That creature cannot be surprised by somebody sneaking around? 

 Yes. The spider sees normally in light. Out to 60 ft in the darkness (as if it was dim light). And it just "feels" anything within 10 ft of it, due to blindsight. Blindsight (10ft) means that if you come within 10ft of the spider, and you're invisible or hidden, it'll still see you, and therefore you won't gain any benefit you'd normally get from being unseen (which normally is having advantage on attacks against the thing that doesn't see you, and it has disadvantage against you).

Quote from soso1234 >>

Web actions says "The target is restrained by webbing" so can the target be huge creature or larger?

 I'd assume so. And I'd just base it off of simple logic - webbing an entire building or a gargantuan dragon might be crossing the line. All depends on the context and the DM, I suppose.

What if a character is reduced to 0 hitpoints by the bite? Does the poison automatically stabilise them?

By bite I assume you mean the piercing damage, and I'd assume not. If so, how would it eat anything it caught?

Yeah, I had an npc go to 0 Hp from the piercing damage,  which meant the poison damage caused 2 failed Death Saves, unless all the damage goes through together.

Since the character was already down, I figured that the poison would stabilise the character,  to keep the Spiders' food fresh until they wanted to eat

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are spiders a good in counter .

Quote from soso1234 >>

Web actions says "The target is restrained by webbing" so can the target be huge creature or larger?

 I think this is covered by the DC12 STR check. These larger creatures will have big bonuses that make breaking free pretty easy.

i,am scared of spidersssssss

@BuBBleyBuBBles  Yes, I had a giant spider as the final enemy in a quick game with 3 level 2 characters and it was the perfect difficulty. You should use it!

My son wants his character to be a spider, could he adapt this?

Thanks

If one were to make their own figurine of a Giant Spider, or any large sized creature, if a block was 5 ft by 5 ft, how many blocks would it take up.

All this here Matt Mecer speaking all about its name and telling you how to say it all I can sya is wow so good, it just made my whole day learning about all these giatn spiders and such

I can't see the CR on the thingy

The CR is 1 (Says challenge: 1 (200 XP))