Unfortunately, Crab Spiders do not get access to the “crab walk” travel power.
Villains can create an Arachnos Soldier epic archetype after they get a single villain to level 50. Despite the “epic” descriptor, they’re not really more powerful than the other villainous archetypes - just different.
They create unique costumes that are in tune with the Arachnos theme, and progress through different branching powersets. At first, they only have access to the Arachnos Soldier powerset, which is a mix of ranged assault rifle attacks and melee assaults, including one area of effect Venom Grenade. They also start with an initial secondary powerset, Training and Gadgets, which gives them a number of excellent buffs along with some utility skills like Call Reinforcements, which brings in several dumbfire pets into the mix.
Once an Arachnos Soldier reaches level 24, they can choose between two paths: Crab Spider and Bane Spider. Crab Spider gives you several additional self-targeted defensive armor buffs along with a self heal and the ability to call in spiderling reinforcements. Bane Spider is a more involved powerset, giving you many new melee attacks that change the focus of the archetype entirely. Most of the attacks do high damage along with a poisonous damage over time component, and it lets you use abilities like Mace Beam, which act as a ranged knockback. They’re for the more offensively focused Arachnos Soldier, although you’ll still have access to the excellent Training and Gadgets tree.
Arachnos Soldiers can choose to go down a different path if they wish by respeccing their characters. The villain epic archetypes are very different from their heroic counterparts in that they work well either alone or in groups. They have no notable weaknesses, and they aren’t locked out of any additional power pools, although they don’t start with any inherent travel powers. While they must look like an Arachnos Soldier when they start out, they get to unlock an extra costume slot at level 10, earlier than most other character types do.
They’re a new archetype, only having been released in issue 12, so they’re still relatively uncommon. Their secondary pools provide truly excellent group support, as the abilities stack with one another, allowing them to greatly increase the defense of their group. Their damage is very good as well, and the amount of customization that you can put in - choosing to be either melee or ranged, defensive or offensive - makes them a fun character to design.
They’re a very powerful support and damage class that works well at any level.