Definitely not to be underestimated, especially the varieties that aren't green, as they can be incredibly deadly to the touch, as even the green slime is acidic to the touch.
There are three major varieties of slime, green slime, blue slime, and black slime, which is known as the silent and invisible killer.
Rewards: 15 Credits
Drops: Every 3 Kills a player can receive a <Slime Core> item.
Green Slime King
Rewards: 40 Credits
Drops: Every 2 Kills a player can receive a <Slime Skull> item.
Green slime is often found roaming the fields outside of the town, preying on unprepared or ignorant adventurers. They are definitely the most "newb-death" monster due to the simple fact of how acidic they are. One touch will deal harsh damage due to the acid property and many make the mistake of touching it first. They are nearly immune to all Slashing and Piercing attacks but it seems a good strong blunt smash can destroy them rather easily due to the smashing of their Core. Alternatively, upon killing large amounts of Green Slime, the Green Slime King may spawn. This monster is a Field Boss and is extremely dangerous to those who don't know how to properly use the Tyr System. The only difference between the Green Slime and their Green Slime King is that the King MUST be attacked in it's skulls for damage to be dealt and it is susceptible to all types of damage.
Rewards: 30 Credits
Drops: Every 3 Kills a player can receive a <Slime Crystal]> item.
Blue Slime King
Rewards: 60 Credits
Drops: Every 2 Kills a player can receive a <Emerald Ore> item.
A slightly rarer breed of slime, these blue slime can be particularly overwhelming, one reason being is that they can solidify their form to do more damage than a green slime and every hit causes the Poison Status Effect, constantly draining the life of their opponent. Like their Green Colored brethren they too possess a King that appears. Don't be fooled by the blob-like appearance of their King either, these demonic piles of sludge can only be defeated if one attacks the green orbs found on the outside of it's body. Blue slimes have no resistance against any weapon type in particular but are still rather dangerous and often attack in groups of three or more.
Rewards: 130 Credits
Drops: Every 3 Kills a player can receive a <Slime Fang> item.
Black Slime King
Rewards: 170 Credits
Drops: Every Kill a player can receive an <Eye Of Midnight> item.
The rarest slime of all, this one is a silent killer and basically the GM's way of keeping new players from raiding the strongest dungeons trying to cheap their way to an easy game. They are practically invisible and dead silent. Hiding up on the ceiling, they surprise their victims by dropping from the ceiling and then forcing themselves onto the body of the victim. Like Green slimes they are acidic to the touch making them all the more dangerous to unsuspecting Adventurers who seek the wonderful treasures of ruins placed around the in game world. These beasts are definitely not kind, and suffocate at an alarming rate, leaving unaware travelers unable to react before their game ends. Much like green slime though, they are incredibly resistant to slashing and piercing attacks. Those who manage to break free and kill off a few Black Slimes are confronted with a scarring and frightening behemoth that looks like something out of a Silent Hill game. The Black Slime King which can only be harmed when one targets the glowing eyes it has, but even that won't save many unskilled adventurers as the Black Slime King is extremely powerful, fast, and even able to launch blobs of it's black goo onto enemies and deal continuous damage over time.