Regular Sentry Beam
These are normal, purple-colored Sentry Beams with two yellow eyes on their heads and a purple and red base. This enemy usually fires red-colored, circular lasers when Mario/Luigi gets nearby. If Mario/Luigi jumps on its head, a spring pops out of it. If Mario/Luigi jump on the enemy when the spring is sticking out of its head, they can get a high bounce off the enemy into the air. This makes regular Sentry Beams useful in reaching objects high in the air, such as Launch Stars, Sling Stars and Power Stars. Another enemy that operates much like regular Sentry Beams (only when it comes to the spring part) is the Spring Topman. These Sentry Beams can be stunned with a jump on their head, throwing a Bob-omb at them, or by firing a Star Bit at them via the Star Cursor.
Spiked Sentry Beam
This is a type of yellow Sentry Beam with a bullet's tip-shaped head. Its head is covered in spikes, preventing it from being jumped on. This enemy also has resistance (protection) from Star Bits being fired at it, meaning it cannot take a Star Bit fired at them. Since their is no way to stun this type of Sentry Beam, they must be avoided at all costs. On the Landing Platform of the Dreadnought Galaxy, there are lines that show how far these enemies' shockwaves can go.
Nut Sentry Beam
This a rare type of Sentry Beam appearing on the Poke Ball Planet of the Buoy Base Galaxy in Super Mario Galaxy. Hence the name, it is a Sentry Beam that is shaped like a nut (tool). It is colored yellow. Even though it looks very different from regular Sentry Beams, it attacks just like them. On the other side of the Poke Ball Planet is another rare type of Sentry Beam.
Bolt Sentry Beam
This is a rare type of Sentry Beam that appears on the Poke Ball Planet of the Buoy Base Galaxy in Super Mario Galaxy. It is found on the side opposite the Nut Sentry Beam on the planet. This enemy is shaped like a yellow-colored bolt. It attacks just like regular Sentry Beams even though the two look very different. Also, it is required for Mario/Luigi to Spin on this enemy's bolt head to get rid of it. This causes the Poke Ball Planet and reveal its inside, which is covered in water. The heroes can then swim to the Power Star.
Mobile Sentry Beam
This is a gray Sentry Beam with menacing eyes that has the power to move, hence the name "mobile". It can move with the help of a propeller on its underside. However, even though it could move if it wanted, most mobile Sentry Beams do not do anything but hover in one place and turn to face Mario/Luigi before attacking. Also, these enemies attack different from other Sentry Beams. Instead of attacking Mario/Luigi with red-colored, circular lasers, this enemy will fire a yellow laser at them from its mouth when the heroes get near. This laser beam is very fast and more difficult to avoid than other Sentry Beam's attack. If hit by this enemy's laser, Mario/Luigi will be electrocuted and lose one wedge of health from their Health Meter. Even though it cannot be defeated, this enemy will cease all movement if Mario/Luigi stands on its head. When they jump off its head, it will continue to attack him until they run too far away to attack.
Rare Green Sentry Beam
This Sentry Beam only appears at the top of tower of the Buoy Base in the Buoy Base Galaxy. It is a green, odd-looking Topman that resembles a Spring Topman. When Mario/Luigi reaches the top of the tower, instead of firing red-colored, circular lasers at the heroes, this enemy releases three Micro Topmen to attack them. Much like regular Sentry Beams, a spring pops out of its head if it is jumped on. Mario/Luigi can then jump on the enemy's head once to bounce high up in the air.
- It is to note that the spiked Sentry Beams that appear in the Shiverburn Galaxy fire yellow-colored, circular lasers instead of the normal, red-colored, circular lasers. This shows that the lasers are indeed electric rather than just being regular laser beams.