Credence still hasn't found the child but naively asks Graves if he can see some more magic. Cue Grindelgraves losing his temper, asking what Credence's mother does when he fails and following through with giving Credence a belt-lashing that'd make Mary Lou proud.

Then the added headfuck of Grindelgraves bending Credence over and raping his sorely beaten and bruised ass while telling Credence how much he cares and it's all Credence's fault that he's doing this.

RACCOON PATRONUS BONUS: The only reason Grindelgraves doesn't summon the obscurus is because he does show Credence some magic - the obliviate spell.