Colloportus

Colloportus is a spell that seals a door so that it cannot be opened manually. There are conflicting accounts in Harry Potter and the Order of the Phoenix as to whether or not Alohomora is a counterspell to Colloportus; one would think that, would Alohomora work against Colloportus, all the Death Eaters would know to use it against Harry Potter's, Hermione Granger's, Neville Longbottom's, and Luna Lovegood's spells in the Ministry of Magic.

Colloportus is first used in Order of the Phoenix.