I found them on my own. Well kinda through a sort of natural progression of liking bands I heard on the radio. It started with bands like Breaking Benjamin, Trapt, Chevelle and Three Days Grace, then noticing they all cited Tool as an influence and then paying more attention to Tool on the radio as they came on. Then I realized "oh they wrote that song and that other song too okay." This was around 2003 so not too long after Lateralus came out. Then I finally decided I needed to get their music. So I wrote down the songs I knew I liked, and when I went to the record store I looked at which CD's had which songs and I ultimately got Aenima first. Then Lateralus, Undertow, and Opiate. Not too long after I had got up to date 10KD came out and like I was saying to Invictus, I rode the cycle of them releasing an album. That's how I got into them.
The songs off Aenima are what hooked me. The aggression and outwardly expressed anger of the title track really spoke to me at just the right time in my youth. Long story short, I had plenty to be angsty and angry about come my teenage years so Tool really addressed that and allowed me to express it in a harmless way. Then delving into Lateralus took that anger and turned it into a really positive outlook on life and myself.
I didn't really have that problem because I kinda learned how to play bass by learning Tool songs. The first riff I ever learned how to play on bass was the main riff from Schism. SO right then and there I was playing 6/4 time I just didn't know it yet. I also took guitar lessons and that helped a lot to. Now I sort of have the inverse problem of people trying to learn syncopation and odd time, I find it harder to write a straight 4/4 riff than I do in something like 5/4 or something really syncopated. Thanks to tool and all the post rock/metal bands I listen to like Isis, Karnivool, Russian Circles and a list of other crazy stuff, I eat that crazy SH*T for breakfast as a musician. LOL
What I love about Tool's music is how it defies convention at almost every turn. You've got a bassist playing guitar range stuff, a guitarist who isn't trying to cram a million zillion notes into every .5 seconds of musical space, a singer with a great range and a really unique voice, and a drummer who titanically thunders out math equations, then all of them rather weird esoteric individuals who are into some really deep trippy stuff.