Corrosive Marauder

Some rogues choose to undergo intense mutation processes to enhance their physical capabilities by combining them with the protoplasmic magical properties of oozes. These fast skirmishers and superior combatants are perfectly adapted to a variety of combat situations, excelling at close encounters thanks to their slippery maneuvers and corrosive skin.

Oozing Essence

You can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check, and you have advantage on checks to escape the grappled and restrained conditions.

Stretching Arms

If the attack hits, the creature receives an additional 1d6 Acid damage. This feature can be used with Sneak Attack, as long as the necessary rules are met. You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a short or long rest.

Abrasive Runaway

This line originates in the position where you used any of those actions, and lasts until the start of your next turn. A Large or smaller creature that comes into contact with it must succeed on a Dexterity saving throw or be knocked prone. 

 

Additionally, when you are hit with a nonmagical melee weapon, your acrid blood corrodes it and takes a permanent and cumulative -1 penalty to damage rolls after dealing damage. If its penalty drops to -5, the weapon is destroyed.

Tugging Strike

Additionally, up to four creatures of your choice that failed the saving throw are pulled up 5 feet straight towards the target of your sneak attack by thin, yet strong, gelatinous arms, and are restrained until the end of your next turn. if the target of your sneak attack moves before this feature ends, creatures affected by this feature move with it, halving its speed and being unable to use reactions. 

 

Once you use this feature, you can't use do so again until you finish a short or long rest.

Fission

This replica has half  of your current hit points (rounded down), is immune to all conditions, and shares your AC, saving throws, and initiative count, taking its turn immediately after yours. It cannot wear any armor, weapons, or magic items that affect its stats, but it can be used for flanking. You can mentally command it on your turn to move up to 30 feet in any direction (no action required), and use a bonus action to order it to use any of the following actions on its turn:

• Engulf. This clone grows and tries to engulf a Large or smaller creature within itself. The target has to succeed on a Strength (Athletics) check or be restrained. The creature can repeat the saving throw at the end of its turn, but it takes 2d6 acid damage and 2d6 bludgeoning damage for each turn it fails to break free from your clone.
• Acid Spit. Ranged Weapon Attack: + (Dexterity modifier + proficiency bonus) to hit, range 30/60 feet, one target. Your clone throws a sticky balloon of acid to a creature it can see within range. If it hits, the target takes 2d8 acid damage and it must succeed on a Dexterity saving throw or be blinded until is uses an action to wipe off the acidic spit.
• Caustic Fumes. The clone expels strong corrosive gasses in a 20-foot radius area around it. Each creature in the area must make a Dexterity saving throw (DC = 8 + proficiency bonus + Dexterity modifier) or take 5d6 acid damage and have disadvantage on Constitution saving throws until the start of the clone's next turn, or only half as much damage on a successful one. 
• Switch. The clone can swap places with you, if it is within 10 feet of you, without provoking an attack of opportunity.

If two hours pass since the clone was summoned, or it is reduced to 0 hit points,  the clone dissolves into a 5-foot-wide pool of acid. Once you use this feature, you can't do so again until you finish a long rest.