Little Stinker!

Our "he-man" little boy managed to pull himself up in his crib! Dan wisely had to lower the mattress to keep him contained when he wakes up and decides he needs to climb up looking for us.

Is this normal for a "just turned 6 months today" little boy??
I feel like the parents in the opening scene of Superman where the little boy lifts up the car. Let's hope this he isn't lifting Heidi next!