For most recent minecraft.
/damage @e[type=minecraft:wolf,distance=..20,sort=nearest,limit=1] 1 minecraft:arrow by @e[type=minecraft:villager,distance=..20,limit=1]
Note: replace villager and wolf with something else to change the attacker and attackee respectively.
/execute as @e[type=minecraft:fox] run attribute @s minecraft:generic.scale base set 6
Note: replace fox with something else if you are lame. Or replace the 6 with a larger number if you are based and want even huger foxes.