Based on cicadas, Semis are small, yellow bug Badniks with a gray underbelly. They each also have six grey, thin legs, a gray head with large cartoonish black eyes and yellow plating between the eyes, a forehead, and yellow and orange-striped elytra. Each model also has a pair of orange wings that can rotate around each other and a small spike ball cannon attached to their lower body.
In Sonic the Hedgehog CD, Semis appear as enemies in Wacky Workbench. In gameplay, they are found in small swarms on walls, usually in the lower sections of the Round with large hall sections with the bouncing, flashing floors. When the playable character approaches them, the Semis start flying away to the left or right (depending on which direction the playable character comes from). Nonetheless, they will fly towards the playable character, trying to damage them through physical contact, which will happen unless the player performs a Spin Attack-derived move. Semis may also drop flashing, spiked bombs that deal damage upon contact. In addition, these bombs will stick to the bouncy floor and detonate after a while, creating some slight flying debris. Regardless, the player can use the flashing floor to reach and defeat these Badniks with the Spin Jump.
In the Bad Future or sometimes the Present timeframe of the Round, Semis show decay; their armor has partially fallen off, their eyes are cracked, their wings are worn down, and their bomb cannons are damaged, meaning they move around slower and cannot drop bombs. However, it can still pose a threat to the player. Also, like every Badnik in the game, they are powered by Little Planet flower seeds which will pop out of them when they are defeated.
Powers and abilities
Thanks to their wings, the Semis are capable of flight. They are also able to produce bombs that they can drop on their targets.