Goblet of Fire

Dennis Creevey, first seen wearing Hagrid's immense moleskin coat, is Sorted into Gryffindor. On reaching the House table, he tells Colin that he had fallen into the lake and was saved by the giant squid.

When Harry Potter becomes the second Hogwarts Champion, Draco Malfoy starts distributing buttons that alternate between saying "Support Cedric Diggory, the Real Hogwarts Champion", and "Potter Stinks". As Harry heads out for an appointment with Hagrid, he sees the Creeveys, Colin and Dennis, working with one of these badges, trying to charm it to say something different. On his return, he sees that they have not been successful; all that they have managed is to make the badge say "Potter Really Stinks".

Order of the Phoenix

Both Dennis and Colin Creevey are members of Dumbledore's Army. While we don't hear much of them, it seems that Dennis is managing to master some of the more advanced charms, possibly with Colin's help, despite being only second-year.

Deathly Hallows

Dennis and Colin are seen trying to figure out how they can stay at Hogwarts and assist in the defence before the final battle, but Professor McGonagall sends them both away.