At Camp Green Lake
Mr. (Dr.) Pendanski is the counselor for D-Tent at Camp Green Lake. The campers of D-Tent fondly refer to him as "Mom." He refuses to refer to the campers by their nicknames given to them by the other campers of D-Tent and prefers to call them by their legal names given by their parents. The only camper he refers to by his nickname is Hector Zeroni who he calls Zero. He does this because he believes Hector is stupid. Right before Zero hits Pendanski with a shovel, Pendanski kept mocking Zero by giving him simple words to spell. He asked Zero "What does d-i-g spell?" to which Zero hits Pendanski with a shovel and yells at him "Dig!" and then subsequently runs away from Camp Green Lake. This leaves him with a large gash across his nose. In the movie he is refered to as Dr. Pendanski but at the end it is revealed that he is not a real doctor. He along with Mr. Sir and The Warden are all arrested since it was found out that Mr. Pendanski deleted Zero's files under the Warden's orders.
After Camp Green Lake
What happens to Mr. Pendanski after he is arrested is unknown. Mr. Pendanski was likely sent to jail on unknown charges. It is unknown how long he served in prison either.