You need a creature for Wolfkin Bond to target as you cast it. It can't enter the battlefield attached to the Wolf token it will create.
2019-07-12
If the target creature is an illegal target by the time Wolfkin Bond tries to resolve, the spell doesn't resolve. It won't enter the battlefield, so its ability won't trigger.
Enchant creature
When this Aura enters, create a 2/2 green Wolf creature token.
