The swamp lizard is a two handed Ranged weapon. It requires a level of 30 Ranged, Magic and Attack to wield. To be operated, the swamp lizard requires its requisite fuel, guam tar.
Despite being able to perform Magic and Ranged attacks, this weapon requires the user to be in the opponent's melee distance to attack, potentially reducing the practicality of the two attack styles.
A player attacks using a salamander.
With 29 Hunter swamp lizards may be obtained by trapping swamp lizards using net traps or buying them from other players.
When using the Scorch (Slash) and Blaze (Magic) attack styles, the attack speed is 5. When using the Flare (Range) attack style, the attack speed is 4, which is similar in concept to the Rapid style of most ranged weapons.
In its melee mode, the swamp lizard has a chance of inflicting poison starting at 6 damage.
A player wielding a swamp lizard
The maximum hit for magic mode uses the "magic damage bonus" of the salamander. This bonus is not visible in the equipment stats, but is equal to 56 for the swamp lizard.
The max hit (Hitmax) formula for salamanders is as shown in fig.1., where "Magic" is your visible magic level and "Bonus" is the "magic damage bonus" for the salamander, in this case 56. This gives us the formula for the swamp lizard as shown in fig.2.
This means the swap lizard will have a max hit of 6 damage at the minimum 30 magic required to wield it, up to 19 damage at 99 magic.
For an exhaustive list of all known sources for this item, see here