Gambrodon lizards are herbivorous critter from their native planet Runksukka. They are also very popular pets in Makuhero City because of their cute appearance, playfulness of a puppy and curiosity of a five-year-old. The idea behind this lizard was to use very similar head than the mutated one's but with huge, cute eyes and blunt teeth and a lizard-like low body build. The tail is rather similar to the big one. I looked HF Brain Attack screenshots to see how the official characters mutated with the slugs: The body build altered but the head was pretty much the same.
And so, when a vicious brain slug attack and attaches itself to Gambrodon's head, it launches a very fast and nasty evolution...
...And turns the cute critter into terrible dinosaur.
I haven't built that much animal creatures with Bionicle/HF parts so this was an pleasant challenge. It started with the head. I had had a similar head tablescrap around for few months, and I took it and gave it more evil-looking eyes, some more teeth and built that red brain-slug. It was easier to integrate a brick-built slug into the head and I don't even have any of those official ones.
The tail was interesting. I needed a tail heavy enough to balance the MOC, but stiff enough to keep the pose. Those two-toe feet pieces worked surprisingly well. They are connected to basic HF joint pieces with one ball on the middle. The tail can be posed, but is held together firmly enough to keep it stiff. The spikes on the tip on the tail create a connection with the shape of the head, and the red pattern on Skrall sword adds a color splash to associate with the red slug.