Walter is Pretorius's 210-cm tall, silent and indestructible goon, but not as murderous and cruel. He is a recurring villain in the animated series The Mask.
He is mostly seen working for Pretorius though sometimes he appears on his own. He chased the Mask for several episodes, but when he obtained the wooden mask and it failed to work for him (a moment taken directly from the original Dark Horse Comics in which "Walter" was a recurring character), he simply dropped it.
Walter remained a recurring character throughout the series. He is strong enough to actually break the Mask in two (an impressive feat as only seconds before the Mask withstood being hit by cars and run over by a steamroller without a scratch).
In the episode "How Much is that Dog in the Tin Can", it was revealed that he was locked up in the same prison as Willamina Bubask.