Effect # 87 on the mini Kaos pad is a Bass looper.
The looper samples a few seconds of the prior accords when you touch the pad.
Once you sample a verse, you can manipulate the loop sequence by moving your fingers on the pad.
The X axis on the pad manipulates the loop beat.
The Y axis on the pad manipulates the loop reverse-forward (cross fade).
The loop sequence will be played until you remove your hand from the pad.
The looper is sampling only a few seconds but you can add more to it as you play along if you do it quick.
You can still play freely and manipulate the loop, while one of your fingers is on the pad
You can find out more about this instrument at it's project page