The Carrionites appeared in “The Shakespeare Code”, Series 3 Episode 2, where The Doctor and Martha met Shakespeare, and The Carrionites planned to begin their new empire on Earth.
Lilith could take human form, she could change from human looking to Carrionite in a matter of seconds. The Carrionites are witch like villains, with very sharp teeth. (Can be seen below).
Rexel 4 is the planet of the Carrionites. Carrionites use words as a weapon; the right words in the right order are power for them and using this they can cast many spells. The Eternals banished the Carrionites along time ago using powerful words. However William Shakespeare set three Carrionites free; Lilith, Mother Doomfinger and Mother Bloodtide as seen in “The Shakespeare Code”, this was the cause of Shakespeare going through a time of madness as his son Hamnet had died. The Carrionites used this time as an advantage and put words into his head which he then used in one of his plays and therefore freed the three Carrionites.
Carrionites also cut peoples hair and attach to a voodoo doll (Described by The Doctor as a DNA Replication Module), this works as a voodoo doll and was seen when Lilith drowned Lynley internally, The Doctor described it as “An invisible blow”. (Lilith with Voodoo Doll can be seen below)
The Carrionites used The Globe Theatre as a desperate attempt to free the other lost Carrionites trapped in the sphere. The Architect was influenced by the Carrionites to build The Globe Theatre with 14 sides, 14 sides because the Carrionites come from the "Fourteen Stars of the Rexel Planetary Configuration.”. The Doctor used the power of the name against the Carrionites when with the architect, to banish the Carrionites away from them. The Doctor did this by saying “I name you Carrionite”.
Lilith used a potion to take over Shakespeare making him write the last words of “Love’s Labour Won” as a spell which would free the Carrionites from the globe. When the words were spoke from Shakespeare’s pay “Love’s Labour Won”, The Carrionites were set free in the middle of The Globe Theatre. (Can be seen below)
When the Carrionites were set free from the globe, an ominous pink/purple glow was produced. The Carrionites from the globe looked completely different to the three Carrionites; Lilith, Mother Doomfinger and Mother Bloodtide. The other Carrionites coming from the globe were airborne and gaseous. (Can be seen below)
At the end of “The Shakespeare Code” the Carrionites were trapped inside the Globe, The Doctor took the globe and placed it in the Tardis, where their screams couldn’t be heard.
There may be a return of The Carrionites, they could somehow persuade another playwright or someone else to use words to free them from the globe. After all The Carrionites aren’t dead so they could always return one day.