I've now collected a list of 10,800 URLs coming from Googlebot which hit my sites search function with random, off-topic searches. Has anyone seen this before? Where do they come from? How do I get rid of them? My concern is that they are indexed by Google, so they are taking up valuable indexing with which I'd rather index my real pages. For now, if I see it's one of the 10,800 random searches with no relevance or meaning on my site, I 404 it. And in Google Webmaster, I am seeing that they are marked as 404. Does that mean Google will hopefully nuke those URLs from its index some day? My site deals with golf - here are some searches to illustrate:

billabong truckin sweater plum
billabong tulip luggage pink lady
billabong turmoil zip hoody black
billabong turmoil zip hoody navy
billabong upper deck t shirt athletic
billabong vernon walk short white
billabong vertigo walk short desert
billabong young folk hat black
billion dollar brow brow powder taupe
billy jealousy hair
billy jealousy lightning bolt electric shave
billy jealousy liquidsand cleanser
billy jealousy white knight cleanser
binding t3 automatic
binding touring auto nnn
biochem 100 berrie whey 1 39lb
biochem 100 green whey protein 2
biochem 100 hemp whey 11 7oz
biochem 100 raw food whey 11
biochem 100 whey protein 2lb
biochem 100 yams whey 11 7oz
biochem 5 htp tryptophan 50 mg
biochem aller max caps 50 vcap
biochem alpha lipoic acid 100 mg
biochem dhea 25 mg 90 caps
biochem glucolean 120 tabs
biochem glucosamaine chondroitin 60 caps
biochem green whey protein bar 12
biochem lipoic acid time released 60
biochem phosphatidylserine complex 30 gels
biochem r lipoic acid 60 vcap
biochem tension rx nighttime 90 vcap