I think this may be George R. R. Martin's "Tuf Voyaging" (1986).
In the first part of the book, a team of archeologists and mercenaries discover the Ark, a huge and powerful ecological war ship dating from a long-past interstellar war. The team falls apart quickly as everyone tries to gain control of the ship for themself. One of the mercenaries gets control of the Ark's biological weapons system (monsters from hundreds of different worlds) and starts using it against the others.
Here's the spider-like alien with ultra-thin legs:
A spider, then. A weird one. The rocky appearance made him think it was some kind of silicon-based life. He’d heard of that, here and there. It was real goddamned rare. So he had some kind of silicon-spider here. Big deal. Kaj Nevis moved closer. Damn, he thought. The web, or what he thought was the web … hell, the damned thing wasn’t sitting on the web, it was part of the web. Those fine, thin, shiny web strands grew out of its body, he saw. He could barely make out the joinings. And there were more than he thought—hundreds of them, maybe thousands, most of them too thin to be seen from any kind of distance at all, but when you looked at them from the right angle, you could see the light gleaming off them, all silvery-faint.
And yes, the ultra-thin legs are shown to slice-and-dice very nicely.