In the world of guitar, “spider” exercises are patterns that point to stretch the fingers of his left hand with complicated positions or string jumps.
Usually made on the guitar, I made my own version on ukulele, with a fingerstyle fingering for the right hand.
This is the pattern for the left hand:
and a short animation that explain the fingering for the right hand (T-A-M-I-T-M-T-I)
As with all exercises, and important to start very slowly. Once the movements become ‘natural’ (and the ‘muscle memory’ begins to do its job), you can increase the pace of the metronome, always paying attention to fluidity and clean of execution.