U-3 'scissors' at the enemy 1-4 times from underground.[excerpt 5] It can be avoided with the Action Button.
U-3 will be encountered during chapter 5-3 at the Luggage containers area. During the initial encounter U-3 can not be killed, the player must navigate and escape the three containers while avoiding the monster. There are three containers, the player can only move from one to the next by locating the two emergency switches and then heading for the exit. When both switches have been pressed, the container will drop after 30 seconds. Not escaping results in death.
When the encounter begins, U-3 will be next to the player and start attacking with "Tentacle bashing" and "Tentacle grab" moves. Doing so much damage to it will cause it to jump up on the rafters out of sight for a while, but it will eventually drop back down. While on the ceiling, U-3 can use the "Ceiling tentacle grab" move. If the player fails to dodge with the actions buttons, they must use the shake off command to break free. In the second container, there will be one scripted event where U-3 will drop down. In the last container after pressing the first button, U-3 will drop down and sprout out a new pincer appendage. It will now be able to use the "Scissor attack" and "Ceiling scissor attack" moves.
The player will be safe upon escaping giving them a chance to heal, reload their weapons, and pick up a few nearby items. Advancing forward a few steps will trigger a cutscene where U-3 attacks again and then the player must fight until they defeat the monster. After a set amount of damage, U-3's attack pattern will change and start to exclusively use the pincer. U-3 will drop 50,000₧.
In the first stage of the battle in the container pods, the U-3 can not be killed and the damage does not carry over to direct fight. When U-3 is on the ground, use the TMP or a shotgun to repel it back to the rafters, or try to run past it without fighting if you are low on ammo as you will need every bit of it in the next portion of the fight. Keeping your fingers on the dodge buttons is recommended as the U-3 will attack with dodgeable attacks, both from the rafters and from the ground level. When U-3 initially sprouts the deadly stinger-like Plaga it will be right in front of the player, tossing a hand grenade or using a magnum shot would be safest and quickest way to repel to not risk being attacked.
The head on fight with U-3 is extremely difficult. Most handgun bullets will do next to zero noticeable damage, and shotguns becomes less effective now that U-3 is able to attack at greater range, thanks to the Pincer Plaga. The best strategy is to use the gates to stop U-3's movement while you unload rifle, TMP, or Magnum rounds. Make good use of the two explosive barrels in the area. One is located in the cave, and the other is located behind the rock in the open area. After receiving a large amount of damage, the U-3's lower section will die, spewing blood and remaining still. However, the Pincer Plaga will still be alive and deadly. Distance is essential. Shortly after rising from the ground again, U-3 will burrow under the ground. After a random amount of dodge sequences, the U-3 will surface, giving you a small time window to attack, but be sure to stay on your toes; U-3 has an instant kill attack where its pincers will cleave Leon in two. U-3 is not easy to kill, and on Professional mode, it is not uncommon to use upwards of 25 Magnum rounds, 30 rifle rounds, 300 TMP rounds, 5 or more Frag and Incendiary grenades, and 50 shotgun shells, or more. Also, on Professional and Normal modes, even a rocket is not enough to kill it. On professional mode, you will still have to unload a fair amount of ammo to kill it, but on Normal it will die in just a few shots after using a rocket launcher. Make sure you're well stocked before the battle. It is also wise to unload rifle rounds onto the orange part of the Plaga, located between its pincers, which has been rumored to be its weak point.
↑触手を振り下ろして床にたたきつける｡ 当たると相手を転倒させる｡ (Shokushu o furi oroshite yuka ni tatakitsukeru. Ataru to aite o tentō sa seru.?)
↑ユニットの上から触手を伸ばし､ つかんだら首をしめつつ天井に持ち上げたのち､ 頸椎をへし折る｡ (Yunitto no ue kara shokushu o nobashi, tsukandara kubi o shimetsutsu tenjō ni mochiageta nochi, keitsui o heshioru.?)
↑背中のハサミを前方へ突き出して相手を切り裂く｡ 第3形態のときは1〜4回連続して使うほか（ただし､ 命中したらその時点で攻撃を上める）､ 攻撃中に相手がいるほうへ向きを変えるようになる｡ 目の前に鉄柵がある場合は､ ハサミを持ち上げて身がまえたあと切りかかり､ 攻撃すると同時に鉄柵を壊す｡ (Senaka no hasami o zenpō e tsukidashite aite o kirisaku. Dai 3 keitai no toki wa 1 〜 4-kai renzoku shite tsukau hoka (tadashi, meichū shitara sono jiten de kōgeki o ue-meru), kōgeki-chū ni aite ga iru hō e mukiwokaeru-yō ni naru. Me no mae ni tessaku ga aru baai wa, hasami o mochiagete mi ga maeta ato kirikakari, kōgeki suruto dōjini tessaku o kowasu.?)
↑通路の上からハサミを突き出して相手を切り裂く｡ (Tsūro no ue kara hasami o tsukidashite aite o kirisaku.?)
↑地中から井ハサミを1~4回突き出して相手を切り裂く｡ (Chichū kara i hasami o 1 ~ 4-kai tsukidashite aite o kirisaku.?)