I beat the cat by having :
- max constitution ,min strength ,min wisdom this minimizes his damage and give you as much hp
- be a rogue and us smoke bomb because its an evasive encounter I think
- edit: you might need to try multiple times for enough damage and I had rogue lv2
- to get the right stats you can use the minimise dice number and maximize dice
- you need to use them on the side where you see the Dice nunber + Dice number(for example 6+1 on strength you use minimize on 6 and it becomes 1+1)