Lagas was the pen name of Belgian comic artist Denis Pierard. He graduated from the Academy of Fine Arts in Liège in 1961 and started his cartooning career as the apprentice of Mittéï for Tintin. Besides several independent gag strips, he also created gags starring the caveman 'Ptyht-Thett' between 1966 and 1969. By 1968 he became a regular in Spirou, creating 'Sam et l'ours' for the magazine's mini-books section with Paul Deliège.
The series about the endless efforts of a hunter called Sam to catch a bear, was eventually also featured in Spirou's normal pages, where it remained a regular feature until 1983. In the 1983-1984 period, Lagas returned to Tintin with short stories starring a new character called 'Rody'. He then left the field of comics and became a designer and illustrator for wishing cards, advertisements and illustrations.