Sourdough the Evil Sandwich was (formerly) Queen Entozoa until they were revealed to be some sort of spirit or energy being who possesses people's bodies for 1,000 years, but because of Wander, they're now a sandwich and now wants revenge on Wander, Sylvia, Lord Hater, and Peepers.
They are voiced by Rich Flucher
Sourdough looks like an average cheese, lettuce and ham sandwich, with the two olives on it acting like its eyes but its true form is that of an amorphous and glowing purple entity outwardly resembling some sort of slug/dragon hybrid.
Sourdough is a truly evil and purely tyrannical being. It detests weakness and desperation above all else and prefers displays of power and acts of defiance. It admires power and reputation, which is something they look for in its hosts. It's also very temperamental and very protective of its planets.
The Fancy Party
Althought he isn't actually a villain, Entozoa had invited Wander to her party because he is the "number one most wanted fugitive in the galaxy" thus doing that turn him a villain.
During the party, she initially didn't like Lord Hater and was constantly annoyed by his attempts to win her over, such as singing her a sappy mushy love song, but after seeing his ruthless display of power, she seemingly grew "fond" of him (but in actuality she became fond of his power).
She was originally going to give Wander her power but instead, Lord Hater proved to be more gruesome and rebarbative, so she gave him her power. It turns out that her "power" was a slug-like demon which had taken over her body 1,000 years ago and was the true puppet master of the queen and it planned to take over Hater as its next host. The slug then entered Hater's mouth, choking him, so Wander did the Heimlich to save him, causing the slug demon to be spat out and land into a sandwich, causing it to become Sourdough the Evil Sandwich.
In The Axe, Sourdough had taken over many of Lord Hater's planets, and so Hater tried to take them back. Enraged that he hadn't properly done so (only planting flags), they chased after them in their ship, firing lasers at them. After Hater made up with Peepers, they took care of the situation and defeated them.
The Battle Royal
Sourdough makes a brief appearance in this episode, seen fighting among the other villains in order to get the ring of power. Wander stopped them, grabbing and throwing them into a pile of normal sandwiches, causing Sourdough's minions to look for them.
Sourdough in their true form is capable of possessing another being and taking complete control of their body, however it can only do this once every 1,000 years. Once it possess someone, Sourdough can apparently keep its host alive for 1,000 years until it ready to get a new one. It can even keep something like a sandwich fresh for a 1,000 years and allow it to survive all manner of physical harm only to come back fully healed soon after. However, its current form is completely powerless and defenseless, leaving Sourdough as nothing more than a helpless sandwich that can stay fresh far longer than other sandwiches. Sourdough's true strength though comes from its incredibly old age which grants it lengthy experience, as well as a vast armada and fortune which it has been expanding throughout the centuries. The bulk of its military force is made up of Queen Entozoa's Beefeaters, which have proven to be bigger, stronger and more competent than other minions seen so far.
- They were the first known common enemy to both Wander and Lord Hater.