How do you fight Cow and Golem as Spider?

I don't play Spider nor SSM a lot anymore, so take this advice with a grain of salt.
For Cow, focus on dodging their attacks and hitting spin web. They should be in big trouble once you hit spin web.
For Golem, I can't suggest anything. It's a really weird and unused kit. Only thing I can suggest is not focusing on using spin web on them and instead hitting needler and attacking it.

 

Keep your distance and dodge iron hook. You don't want to go too far away, because needler doesn't go that far.

 

Spider's greatest strength is its speed. Learn to use its directional leaping to its full potential and you'll run circles around most classes in the game.
Cow and Golem are both bulky, so whittling them down with needler spam isn't ideal and will take you a very long time (though it can still work).
Spin web on them if either of them are gaining momentum on you in a fight, or if you're low and need a little regen. It's also a free needler hit as well.

When it comes to playing offensively, make sure you void them instead of just reducing all their HP. This is fairly self-explanatory given how bulky Cow and Golem are. I'd advise doing this to them when using any class, not just spider.

One method of doing this is using spider's leap to help you combo opponents off the edge of the map. You can do this by spamming double jump and left-click, whilst looking at your opponent's legs or feet. Think of it as W-tapping but even better. I advise looking diagonally downwards eg. where the opponent's legs would be, so that your leaps don't take you past them and potentially straight into the void lol.
If this works, you'll melee them into the void and you can then use needler to cancel out their recovery move.

Hope this helps, I'm only an ex-SSM sweat though so maybe this is outdated : )

 

As long as you bait out angry herd and be wary of aggressive milk spiral + melee you should be fine. Both Spider and Cow are my main kits but I'd say cow is probably harder to take down as a spider than vice versa. Whenever I'm playing spider I lead with needler and then use the surrounding terrain to my advantage. Something I see newer spiders do is try to run away from cow which rarely works and if a fully charged stampede hits you your chance of winning the fight is very low. As a cow facing a spider I tend to look to back spiders into a wall and aggressively push with milk spiral.

 

Web, Needle, only approach if caught web, if scared only needle approach with web capture, run run run, always try to go for void kills, if your lucky they just quit all together

 

for golem, keep your distance. abuse your mobility as much as you can. golem up close does a lot of damage, and takes significantly less because of its impressive armor. avoiding the hook is crucial because it will be your doom. if you do get hooked, just respond fast- spin web then get away. staying close means you can get fissured at close range, because fissure is fairly easy to dodge at a mid range. slam also can hurt.

 

You have to make sure that cow doesn’t build stampede bc it’s lethal if it can land it. I would recommend strafing it often to try and bait out the milk spiral. Herd isn’t much of a problem since you can jump over it. Use needler as much as you can since if you can stall their movement for a second, stampede cancels (it cancels on dmg but needler doesn’t do enough). For golem, staying away and waiting for the hook is key. Then you can do lots of aerial attacking and jumping around it. However never jump down on the golem if it has hook available since that’s a free 5 hearts.

 

Cow should be easy for spider as long as you play passively, if you play aggressively cow will just milk spiral you from close range and take and do way too much damage to you to be won consistently.

Golem for spider is entirely about needlering and comboing and webbing them while they're in the air, if your air webs are lacking then you will struggle here.

Overall for golem basic pointers are to avoid getting hooked at all costs and try to get as good at aiming needler as you can, while holding onto web until you see a good opportunity to use it, often players will play very defensively trying to wait for you to use your spin web so they can approach you and then you cannot punish them being aggressive since needler alone really isn't enough to deal with golem.

Wall climb kb cancel is often a good combo starter in other matchups but here I'd recommend against it for the most part since you won't be able to get a combo started on a low health golem. Comboing golem in general in this matchup is completely unviable when the golem is above 50% and good golems will play around that and camp when they start approaching that range.

Your win conditions are dealing enough needler damage to the point where comboing golem is viable and going for webs, if you web them and they don't have their iron hook then you can potentially get a kill off of the web but if the web is below golem they can also slam to defend themselves for a bit.

You can camp on the sides of the map with wall climb if you feel confident but often good players will punish this by jumping down and trading you in melee since you will often only do this if you are low on health and since wall climb disables knockback you will die very fast, and then they will simply double jump and slam back onto the stage. They can also threaten this position with a well timed iron hook which can sometimes net them a free kill.

If the golem won't let you get them low enough to combo them then that's simply the matchup and the reality of fighting golem with spider, it's just not fun.