Gate Clip
Gate clip is used in the 100% Normal speedrun to skip a longer section of the Mothership between the Glass Tube and Early Power Bombs location. Normally you would continue to the top right of the ship and navigate some extra rooms to reach the early power bombs, but performing the gate clip allows you to skip that section completely and reach the early power bombs through much fewer rooms. The downside to gate clip is the pirate manipulation takes quite a bit of time to setup, and you till take 6 hits during the setup which makes the required refill later on take a little bit longer. There is also a frame perfect input required to complete the clip which makes it very hard to perform consistently. Overall this clip should save about ~10 seconds off the run.
The way to set up the clip is to run into the room with the alarm on and grab the right side of the floating platform as soon as you can. Do not hold any directions or any other buttons after grabbing the ledge, just let Samus hang there with her arm pointing down. If done correctly, the pirate will run into the room and knock samus off the platform, do one jump against the gate before turning around. While you have iframes from the first hit, you will want to also run against the gate and turn left. At this point you and the pirate will both be facing left and it'll start shooting at samus continously, and you want to let go of all buttons during this time and take 4 more hits from the pirate, for a total of 5 hits up to this point. After you take the 5th hit, start holding right during the hit animation so that when you land you immediately turn right and run past the pirate. You should have enough iframes to make it back to the gate, at which point the pirate's subpixels will be manipulated into making this clip work. The pirate should turn around and hit you for a 6th and final time, at which point you look straight up and fire your beam once to freeze it.
Once the pirate is frozen, tap down to make Samus crouch, and then tap right for a few frames to make her step into the gate. This clip will push her entirely forward into the gate and will also push her down one tile. Once you're in this position, tap Right and Jump at the same time to make Samus spin jump, and press Jump again after exactly 8 frames to make her clip below the floor. This is the frame perfect input, if you time your second jump incorrectly you'll be stuck inside the gate in a crouched position and unable to move until the gate opens. You can kill the pirates in the room to open the gate and reset the room to try again.
Some advice for pressing jump twice after exactly 8 frames is to watch the blinking minimap in the top right of the screen. Scotty found that blinking animation happens to blink at exactly 8 frames, so you can watch it and try to time your jumps with it. Another tip is to set a metronome to 450bpm and tap along to the beats. Once way I found to do this is by using metronom.us, setting it to 225bpm and doubled it with the eighth note setting.