Monster (Stowaway)

The monster, also known as The Green Terror, was a creature that stowed away on board the Doctor's TARDIS. It gave off a sweet, sickly smell. (PROSE: Stowaway)

Biography
The monster had been caught as a spawn in the First Doctor's jacket on a visit to Slemos. It had been left in one of the TARDIS's rooms, and grew for centuries. When the Fourth Doctor materialised inside solid rock on the planet Neto, the creature attacked the Doctor. K9 Mark II blasted it with his energy beam, and the Doctor retreated to the console room. It was defeated telepathically by the Guardian of Good on Slemos, who was linked to the creature and protected the planet from its instinct to kill. The Doctor trapped the creature in a cage and held it onboard the TARDIS. (PROSE: Stowaway)