Okay. This is a creature which is going to appear on my "Dragona Pine : Starting Point" fanfic, so I thought that I would tell you a bit about it.
Species Name: The Revengors (pronounced "Revenge-ors.")
Appearance: Can be up to ten metres tall, although most of them are about two or under, they have brown skin with sharp claws and teeth, capable of chewing anything it comes across. They have spikes running down their spine and a club made of bone on the end of their tail. They stand on two legs, but can move quicker on four. They have no visible eyes, but instead rely on sound waves like bats, but much more effective. They can see a pin head at a distance of six miles away.
Home: A planet that Grindor once accidentally made a portal too. They slipped through it and reached Earth. The planet is of unknown location and size.
Language: The Revengors communicate in a series of growls and roars.
Behaviour: Ruthless and deadly, will kill anything that moves, and only eat half of what it kills. Mostly pack hunters.
Possible Damage Caused: If a single Revengor was left in London, everyone in it would be dead within a day.
Abilities: The power to create portals, like Grindor Blackout. They can only be summoned by people who can create portals, and teleporters. As well as that, they can only be killed by the person who summoned them, others just slow them down. Even the most powerful of mages can't kill them unless they were the ones who brought them to Earth. Bad news for everyone on the planet if the teleporter or portal-maker is killed.
Intelligence: A bit less than a human, but smart nevertheless. Smart enough to make traps, plan ahead and communicate. If several of them got in our world, they would become the dominant species.