Based on seahorses, Aquis has a yellow and white metallic body. The head section has white eyes, two sharp antennas and a small, vuvuzela-shaped snout. In the neck hole are two bolts set on each side. On the back side is a row of five back spikes. Unlike real seahorses, these Badniks also has small wing fins, although it is unclear if the Badnik can float because of the wing fins.
There are differences between in-game sprites and artwork illustrations, as the artwork shows Aquis to have sharp a spike at the end of its tail, while in-game sprites show the Badniks having a normal tail like real seahorses do. In Sonic Lost World, Aquis' design has been altered with orange back spikes and cyan eyes. However, they do not show having antennas and sharp spikes on their tails.
Powers and abilities
Aquis are able to float and move in the air. It moves around until seeing its target, it starts shooting small black oil projectiles towards its target. It keeps moving around its target, and shooting its projectiles until Aquis itself attacks and floats away. In Sonic Lost World, they have given ability to use snout to suck objects, including Rings.
Sonic the Hedgehog 2
Making its first appearance in Sonic the Hedgehog 2, Aquis patrols the Oil Ocean Zone, there can one or two Badniks at same time. When it sees the player, it starts moving closely forward him/her and shoots oil projectiles. Aquis doesn't move away after that, as it floats around the player for while and keeps shooting more projectiles. Due of this fact, the player would have difficulties avoiding these Badniks and it is better to keep moving.
However after a while, it starts attacking by moving towards the player and then floats away without stopping. The player is able to destroy these Badniks by Spin Jumping on them right time, when it doesn't shoot its projectiles.
An unnamed Badnik similar to Aquis appears at Blue Marine Zone in Sonic Blast. These Badniks scuttle through both overworld and underwater sections of the zone and start firing projectiles. However unlike Aquis, if the player destroys Badniks by doing Spin Jump at right time, they don't have Animals inside them at all.
Sonic Lost World
In Wii U version of Sonic Lost World, the Aquis can be encountered in a secluded passage near the end of Frozen Factory Zone 1. They swoop down from above and use a vacuum attack to steal the player's Rings. Defeating them will release the Rings they stole.
The Aquis' name is based on a combination of the words "Aqua" and "Equus," the former which means "water" and the latter which is the genus that include horses, which is befitting since the Aquis is based on a seahorse.
In the Simon Wai prototype of Sonic the Hedgehog 2, Aquis Badniks have slightly different appearance as having more of a pink color scheme as well. Unlike in the final version of the game, these Badniks also behave more erratically. The Debug Mode object list of Oil Ocean Zone shows a variation of this Badnik that seems to spit harmless projectiles. They are internally known as "seahorse" and "skyhorse", respectively.