Dexter's Laboratory Wiki
Fergie O'Reilly
Aliases Ferguson
Gender Male
Species Human
Family Grandpa (father)
Dextamina (aunt)
Mom (older sister)
Dexter (nephew)
Dee Dee (niece)
Dad (brother-in-law)
Unnamed sister
Occupation Magician
Interests Magic
First Appearance That Magic Moment
Voiced By Mark Hamill

Ferguson "Fergle" O'Reilly is the younger brother of Mom, Dextamina's nephew, and Dexter and Dee Dee's magical maternal uncle. He makes his only appearance in the episode "That Magic Moment".


Fergle O'Reilly is a very short man, just a little taller than Dexter, and has curly red hair (a little darker than Mom's) and black eyes. He wears a formal white shirt and tie with a green jacket, pants, shoes and top-hat. His overall appearance makes him resemble a leprechaun (which he may actually be, considering his unique magical abilities and Irish accent).


Prior to the series, Fergle O'Reilly would visit his sister and her family for some time, even revealing to know some magic tricks, which would involve pulling a rabbit out of his hat, which Dexter found amusing (when he was much younger as he wanted to do magic as well). However, one night, Dexter discovered the secret of his uncle's tricks, so he would stop believing in magic and instead believe in science.

When he arrived, he tried to have Dexter shake his hand, only to reveal it to be a fake hand. After Dexter's experiment caused Dee Dee to disappear and is unable to make her come back, Fergle learned the truth and agreed to help him by bring Dee Dee back by saying the magical word "Abracadabra", which made her reappear. Unfortunately, when Dee Dee began to talk about where she was to the point where she ran her mouth super-fast, which caused him to say the magic words again and she disappeared.

As Fergle prepared to leave and say goodbye to his sister and her family, he whispered to Dexter that Dee Dee will return once he's far away from her and said his goodbyes with a handshake, which Dexter fell for again, as it was another fake hand.


  • He is based on the comedian Ed Wynn.
  • He has not been seen interacting with his father, aunt, or other sister.