Grabbed by the GhouliesG 10

If you don't own the character, you can either wait for it to roll around as the free one or bust through trials until you find one that lets you use the character. I got this via the trials method.

The method:
Use Practice mode or any mode you desire though practice mode lets you give yourself infinite instinct. Once you activate instinct (RB+RT) you must then grab your opponent. (A+X)