Yeah there is!

Or at least I remember being one.
Record the track with your guitar, then go into the plugin menu and choose the pitch shifter.
Set it to -12 semitones and that's that, but the thing introduces a lot of latency so after you recorded the track you may want to move it a bit back into the timeline to get it synced with the rest of the audio.

There's a simpler and better sounding way though.
IIRC, you get asked what kind of track you want to add when you choose to add one.
At that point you choose "software instrument" or something similar, and choose a bass sound ya like.
Then right click on the track you created, and draw the notes of the part.

Might be less immediate, but there's about a 10th of the latency in the worst case, and it will most likely sound way better.
Name's Luca.

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oh wow, thanks so much!
I'm so happy right now I'm going to test that as soon as I get back!

Thanks a lot!!