A is for... Abzorbaloff

Inhabitant of the planet Clom, which is sister world to Raxacoricofallapatorius, home to the Slitheen. The name "Abzorbaloff" is not the species' real name, but one individual who visited Earth in 2007 rather liked the title.
Posing as a man named Victor Kennedy, it infiltrated a group that was dedicated to finding the Doctor. This was LInDA - London Investigation 'n' Detective Agency. Kennedy insisted that the group use more professional means to track down the Time Lord. He began preying on group members, transforming into his fleshy green natural form to absorb them into his body. Victims remain conscious for a time after absorption, and retain their memories and willpower. They can mentally connect with each other. To stop himself from constantly absorbing all around him, Kennedy used a device disguised as a walking cane to maintain his form.
Kennedy wanted to digest a Time Lord to gain all his vast knowledge and experience.
Soon only one member of the group was left alive - Elton Pope. The Abzorbaloff pursued him and trapped him in an alley. The Doctor and Rose arrived, as she was angry that Elton had upset her mother.
The other members of the group that had been absorbed, led by Ursula Blake, joined together to start pulling the Abzorbaloff apart. He dropped his cane, which Elton then broke. The Abzorbaloff was unable to stop absorbing and was sucked into the ground - dissipating him. As the last victim, the Doctor was able to save Ursula, though she existed only as a face embedded in a paving stone.
Clom is one of the planets that Davros and the Daleks stole in order to power their Reality Bomb. It hadn't been taken at the time the Abzorbaloff was active on Earth, as he talks of returning home in triumph once he has absorbed the Doctor.

Played by Peter Kay. Appearances: Love & Monsters (2006).

• As Kennedy, Kaye uses a sort of Received Pronunciation voice, but as the Abzorbaloff he uses his native Bolton accent.
• The Abzorbaloff was the winning entry in a Blue Peter design a monster competition - the creation of 9 year old William Grantham. Grantham intended that it would be the size of a bus, but hadn't specified this on his initial entry.