Magic in the Harry Potter universe ranges from life-threatening curses to charms with much more modest effects. Among the weaker examples are spells that mainly distract, cause inconvenience or, in one memorable case, do nothing at all.
Rictusempra, the Tickling Charm, makes its target laugh and can leave them struggling to fight back. Harry uses it against Draco Malfoy during a Dueling Club match, and it is later practised by members of Dumbledore’s Army. The charm can provide a brief distraction, but its effect is limited.
Point Me turns a wand into a compass that points north. Hermione teaches the spell to Harry, who uses it to navigate the Triwizard Tournament maze. It can help with direction, but a wand being used as a compass leaves its owner without an immediate way to attack an unexpected threat.
Densaugeo is a hex that causes a victim’s teeth to grow rapidly. Draco attempts to use it on Harry, but hits Hermione and Gregory Goyle instead. Its potential seems largely confined to pranks or creating a distraction, rather than causing serious harm.
Orchideous conjures a bouquet from the end of a wand. It appears during the wand-weighing ceremony in Harry Potter and the Goblet of Fire, and Hermione later uses it to make a wreath for James and Lily Potter’s graves. It may suit a romantic gesture or a solemn moment, but has little apparent value in a fight.
Peskipiksi Pesternomi is the most conspicuous failure of the five. Gilderoy Lockhart shouts the incantation at a swarm of Cornish pixies, apparently hoping to control or repel them. It has no effect: the pixies take his wand and cause chaos in the classroom. The spell’s true status is uncertain, but its on-page performance makes it the clearest dud on the list.
Sources: Comic Book Resources.