Resident Evil is an impeccable zombie series iconic for the beloved cast of characters plunged into intense zombie outbreak situations in different parts of the world. While the mutant bosses and zombies share some of the thunder for their impressive designs and mechanics, the virus animals need some affection too.
Ethics not being in their vocabulary, The Umbrella Corporation and its various virus strains have caused irreparable harm to countless species of animals across all the games. And these became some of the most notable and dangerous B.O.W.s you'll get to know closely.
11 Alligators
First introduced as a boss in the original 1998 Resident Evil 2, the alligators resurfaced in Outbreak File #2, The Darkside Chronicles, and rightfully Resident Evil 2 Remake. Outbreak File #2 featured the smaller versions of the big one, but they're equally dangerous since you have to swim around them and try not to get bitten in their zoo habitat.
Leon's encounter with the gigantic reptile in the remake captures solid suspense. Seeing its giant mouth try to chomp Leon from side-to-side inches away as he's running through sewage and debris while narrowly dodging it makes this one of the best boss fights in the game. However, it's pretty short-lived, and there's no combat challenge in defeating it.
10 Del Lago
Del Lago translates to "from the lake," and that's precisely what this creature is. Dwelling in the village lake, it serves as the first boss in Resident Evil 4. It's an amphibian salamander-like animal transformed into this gigantic monstrosity by the Plaga experiments that now prefers to feed on humans.
It's got a mouth as wide as a whale shark that can gulp you up whole, and it also doesn't like you disturbing the water and ruining its peace. If you fire a couple of shots into the water, you're its next meal. This fight is likewise nowhere near as challenging as the rest in the fourth installment, offering you unlimited harpoons to dispose of the lake beast.
9 Stinger
Debuting as the first boss in Resident Evil Zero is the Stinger. It's a giant mutated Scorpion that you fight in a close-quarter encounter in a train car aboard the Ecliptic Express. If you thought the average scorpion was frightening, this one brings a whole other level with its giant stinger and pincers trying to stab away at you.
This isn't the only creepy crawly arachnid you'll see in the Resident Evil universe, as the harrowing giant spiders tend to make their warm welcome sometimes, but the Stinger is much more menacing. Its movement and proximity to you and its razor-sharp appendages are a horrific way to take some damage.
8 Cerberus
The most iconic animal in the Resident Evil series certainly must be mentioned. Even before the gameplay begins, they already tear through the S.T.A.R.S. team and chase them into the mansion. And the nostalgic jump scare of walking past the window in the original game and the dog jumping through, shattering it, is unforgettable.
These zombie dogs are named after the three-headed hellhound of Hades, and these hellish Dobermans become the recurring enemies in the Resident Evil games to come. Over the years, they've undergone significant redesigns, but they look their most ferocious and grizzly in the remakes of Resident Evil 2 and 3.
7 Colmillos
Resident Evil 4 still found a way to include a zombie dog-type enemy and turned things up a notch. They're called Colmillos and are wolves infected with the Plaga parasite. The Plaga element appears on their backs, a long thick layered tentacle sprouting like a vine and attacking you in addition to their scary array of teeth.
Not only did Resident Evil 4 Remake do a great job with all the redesigns of the characters, but also the enemies, as the Colmillos feel more ravenous and eager to bite off Leon's face. They also come with a thicker coat of black fur and a set of beaming red eyes.
6 Neptunes
Resident Evil: Death Island may have teased the animated film version of the zombie shark, but these sea animals were already a part of the series from its start in 1996. Though they also come back in Resident Evil Outbreak and The Umbrella Chronicles, it's the 2002 remake where they're truly terrifying.
Referred to as the God of the Sea, these Neptune sharks swim in your path in the flooded laboratory section, with the most enormous awaiting you deep below. They gladly take some bites out of you and lurk beside your feet, brilliantly building the tension in navigating this area. And the big one can even jump out at you like Jaws.
5 Eliminators
It wouldn't seem like Umbrella to have every other species as a test subject except for monkeys, and Resident Evil Zero addresses just that. The beloved primate animals are revealed to have also become victims of the t-Virus as a B.O.W. known as Eliminators. Like the Colmillos, these love to lunge at you and bite into your neck.
Their design is quite grotesque and among the more underrated ones in the series. They appear to be hairy gray-white monkeys with skin deformities, exposed flesh, and visibly sharp teeth. And it can get pretty overwhelming when you have a horde of these zombie primates surrounding you.
4 Gulp Worm
Native to Rockfort Island is what was once a harmless little earthworm that has now been completely transformed into a colossal mutated sandworm called a Gulp Worm. Its head opens into a large mouth with branching appendages coming apart like a Demogorgon from Stranger Things.
This was a unique mini-boss from Code Veronica and something very different for the series, as a whole, in terms of animal monstrosities. As in the name, these worms will gulp you down whole if you're not careful, and they slither and rise from beneath the ground when attacking.
3 Oscar The Zombie Elephant
The first location in the sequel spin-off Resident Evil Outbreak: File #2 brings you to Raccoon City's zoo. You're met with a deadly barrage of virus-mutated wildlife, but none are such a sight as the set-piece elephant that pursues you through the zoo. Oscar is an adorable name, but the mutation — not so much.
The distinct zombie features on Oscar make him among the best zombie animal designs in the series. From the exposed bone and flesh to the bitten ears with missing chunks to the tusks growing thorns and looking sickle-shaped, you absolutely want to steer clear of this elephant.
2 Yawn
A reptile you encounter in the first Resident Evil game is a giant snake named Yawn, an unfortunate test subject injected with the t-virus experiment, mutating it into this daunting being the S.T.A.R.S. team now has to face. And the name is a lot less innocent than it sounds.
Similar to other giant animals that give chase, Yawn will slither through the halls of the Spencer Mansion, sneaking up behind you at times and attempting to trap you by circling you. Its behaviors are impressive and feel precisely like you'd expect of a humongous snake you see in creature films.
1 Popokarimu
Crows are a big part of the Resident Evil series, appearing as both infected and harmless birds throughout the games. The most notorious example is in Resident Evil 4, where they can bring loot. But Resident Evil 5 additionally goes for bats with its cavern and mine locations, and you get this compelling monster named Popokarimu here.
Its figure resembles a hideous cross between a silkworm-like body and the alien vampire creatures from House of Ashes. It escapes transport carrying within it the new strain of Plaga it received, which gives it this enormous mutated bat appearance with flight incorporated into its design.