Trogg

Troggs were a race of extradimensional creatures and the main antagonists in the animated film, Gnome Alone.

Biology
Troggs are extremely chaotic, mischievous monsters, being rather small with purple skin, red eyes, a round body similar to a ball, a mouth full of teeth, and retractable limbs. Troggs would pretty much consume everything in sight, indicating that they have an insatiable hunger. These creatures would be able to instantly travel to Earth from their own dimension through portals, while Troggs mostly spend time in their homeworld sleeping in large groups. They could even combine themselves into one enormous, colossal subspecies.

Weaknesses
Though Troggs could not be killed, the gnomes used a nectar from a flower which would immediately send them back to their own dimension, but only for a short period.

Pre-historic era
It's possible that when gnomes were prominent on Earth, most Troggs were sent to scout the area where they'd first appear. After sending a multitude of scouts, they stroke when the gnomes were unaware, surprising them. When the gnomes were outnumbered, they possibly fled to a forest where they would later on find a plant which sends them back to their dimension. After several years of the ongoing war, the Troggs fled to their homeworld, waiting for the right time to strike.

Late 20th century to present day
Eventually, a house was built in the exact place on where the Troggs first invaded, presumably in the late 20th-century. This makes it the perfect place to strike, however, because it has multiple places to hide. In response to some Troggs hiding in the house, a group of gnomes decided to settle in the said house (eventually nicknamed "Frankenstein's Castle" in the early 21st century) to send the Troggs back to their own dimension, by bringing the flower with them. It's also possible that the gnomes obtained a piece of the crystal that enables them to travel between dimensions, yet Zanfeer remained behind. Because this crystal piece pacifies the portals, it was later named the "Keystone." In 2019, when Chloe and her mother moved in the house where the gnomes guarded, Chloe eventually took the Keystone, which was mistaken for an ordinary crystal, then made a necklace out of it by tying a piece of string on it. This made the gnomes worry, which would lead to the Troggs invading the house. The first Trogg to invade the house eventually made contact with Chloe, which lead to the gnomes to send it back. When Chloe was later on questioned on where the Keystone is, she responded that she gave it to her friend, Brittany. As the Keystone is now absent, more and more Troggs can invade in greater numbers. Eventually, after Liam joined in to push the Troggs back, he and Chloe wound up in their homeworld, where they'd later on find Zanfeer. When trying to escape, Liam eventually found a solution to blow up the Trogg dimension by having Chloe placing her phone's battery on the crystal, leading to a lithium-based explosion. Yet, when they merged enough, they survived the explosion, leading to a race against time to take down the Mega-Trogg. This lead to its demise, as Chloe threw the flower to the Mega-Trogg's mouth, sending it to the void on what was once their homeworld.