Jerry is a minion who serves as one of Gru's infiltration specialists, which means he's also a pretty fair martial artist.  And yet, in spite of that all, he's a good babysitter too, and can slip out of his professional demeanor into that of an innocent and playful caregiver.

(NOTE: Officially there are two Jerrys in the Despicable Me franchise.  Each is an entirely different type of minion.  This particular Jerry appears frequently in Despicable Me, and is seen assisting Gru and Stuart in infiltrating Vector's lair. He is referred to by name, specifically by Gru, when he and Stuart are asked to look after the girls.  However, he does not appear specifically in Despicable Me 2 or Minions.)