Readers likely will dislike Drummle when Jaggers calls him a “spider,” because this is not a pleasant image. Jaggers rarely gives an outright opinion about something, but he does share insights subtly and is a great judge of character. Drummle has a reaching, grasping, parasitic character.
When Jaggers first sees Drummle, he describes him as a “blotchy, sprawly, sulky fellow” (enotes etext p. 145). He says he likes the looks of him.
He immediately began to talk to Drummle: not at all deterred by his replying in his heavy reticent way, but apparently led on by it to screw discourse out of him. (p. 145)
Drummle’s negative qualities and the creepy factor attract Jaggers. He is interested in him because he sees his true character. Pip doesn’t understand this. He comments that he doesn’t like Drummle, and Jaggers agrees.
“No, no,” my guardian assented; “don't have too much to do with him. Keep as clear of him as you can. But I like the fellow, Pip; he is one of the true sort. Why, if I was a fortune-teller—” (p. 148)
This is an outright statement by Jaggers, followed by a subtle hint. Even Pip, hardly worldy, sees Drummle is trouble. The reader, smarter than Pip, knows that Jaggers’s statement should not go unnoticed. The reader should keep an eye on Drummle.
Pip worries about Estella and Drummle, and notes that the spider “was used to lying in wait” (p. 210). Jaggers tells Pip that a man like Drummle “either beats or cringes” (p. 263).
“I didn't say so, Pip. I am putting a case. If he should turn to and beat her, he may possibly get the strength on his side; if it should be a question of intellect, he certainly will not. It would be chance work to give an opinion how a fellow of that sort will turn out in such circumstances, because it's a toss-up between two results.” (p. 263)
Pip is very upset when Estella marries Drummle, and it seems clear to even him that she has chosen the most despicable man she could find.