Roller

"That's...Uh, it's probably a big pillbug! It's just a pillbug, so...A, a pill!?"

- Associate Professor Marin Honda, right before being crushed by Rollers

Rollers, officially classified as Aggressive Alien Species Gamma (侵略性外来生物γ, Shinryaku-sei Gairai Seibutsu Ganma) are a new enemy introduced in Earth Defense Force 5. They are gigantic pillbugs similar to the Gilio creatures in Global Defence Force, and attack by curling up into a ball and rolling at their targets, though they do not explode like Gilios.

Description
Rollers are introduced midway through the game's campaign, and are often deployed alongside other Giant Insect enemies by Teleportation Ships and Teleport Anchors. Rollers are often dropped in large quantities, and attack in groups. When not curled up, Rollers are completely harmless and move quite slowly. But upon curling into a ball, Rollers become high-speed projectiles that can knock down any EDF soldier unfortunate enough to be in their path. They have two distinct types of attack: they either roll along the ground, or throw themselves at their target in an arc. Their arc actually has infinite range, though this is not usually a factor in normal gameplay: if, for example, the player character is a long way from them after they finish off a group of NPCs, the player will witness a number of Rollers leaping a ridiculous distance into the air to get to their location.

They also have two rolling animations: one is a "travelling" type which they use to travel long distances, strictly following the navigational mesh that is part of the map. They cannot immediately attack out of this animation: rather, they will uncurl and curl up again to enter their offensive rolling mode. If their target is not easily reached by following the navmesh, they will have to uncurl and walk to the proper position.

While easy to kill, Rollers can quickly become a challenge in groups, knocking the player character down repeatedly. However, any damage, no matter how minor, will abort their attack and place them back in their "neutral" crawling state, forcing them to re-initiate their attack. They will uncurl as they are knocked away, which can make it appear as if they have been killed: however, their death animation always has them split in half at their midpoint, so if they do not break in two they are not dead.

A Roller's contact damage is handled as being explosive by the game engine (similar to Deroy stab attacks and a Hornet Queen's darts), presumably for the associated physics effects. This means that, while they cannot destroy buildings, they can destroy some scenery objects that are immune to bullets, such as rock piles. One upshot of this is that if a Ranger is equipped with one of the "explosion proof suit" Support Equipment items, Rollers will no longer be able to knock him down. They also cannot knock down a Fencer if he has his Shield raised or is using any close-range weapon attack that grants him "super armor."

Their knockdown effect also has a special quality in that it removes the normal damage protection while ragdolled, presumably for follow-on hits from other Rollers to be effective. However, it removes this protection for any attack that hits the player character while they are knocked down, making it very dangerous to be hit by a Roller while in a group of other enemies.

Because of their large size and requirement to physically touch their target to do damage, a character cannot be damaged by them in any space too small for them to enter while curled up. It should be noted that they clip a short distance inside a structure when striking it, so being at the very exterior of a building (such as on the outer walkway of an apartment block) is not safe: the structure requires some depth to offer proper protection, such as a parking garage or recessed stairwell.

Rollers are almost guaranteed to get in close, so shotgun-like weapons and flamethrowers are good choices for combating them. Weapons that can be used to screen off areas such as the Ranger's Flame Geyser launchers and Impulse mines, or multi-hit Air Raider area-effect strikes like Spritefall are also very good for keeping them at arm's length. Explosive weapons are generally a bad idea, as Rollers have a nasty habit of rolling right in front of a character as they are firing.

The Air Raider's forcefield devices are not effective at stopping them. A forcefield will only stop a Roller walking through it when it is not curled up: their roll move counts as a physical attack like a Crimson Ant's grab and will pass right through.

Unlike the other Giant Insect enemies in the game, Rollers have no mutant variant.

Trivia

 * In one of the trailers for EDF 5, Associate Professor Marin Honda, having recently joined the Earth Defense Force as a Ranger, was crushed by one of the creatures after assuming they were mostly harmless.