This is a repost of an old strat, but with a visual cue instead of the weird way I did it before. When you enter the GHusk room, jump ASAP and dash when you meet this pointy thing in the foreground (screenshot). You can buffer your first pogo out of the dash, then buffer a second if the big enemy is facing left (first clip) or slightly delay if they're facing right (second clip) to avoid only hitting the background object. In the latter case, you'll also wanna do a turnaround slash as you enter the tunnel. This will give you at least two extra hits of soul before GHusk and will ensure that the fireball after will kill the big enemy instead of having to hope it'll double.
Greeding this is not always necessary for it to work but is recommended. Less greeding will eventually cause the right case to fail (third clip). For best results on both enemy patterns, the first dash should be as low and to the left as possible while still going over the enemies.
beginner tutorial for 1221 double spike. shows simple example of how to perform, and then explains more in detail, and attempts to go through in a way to help understand the most common issue with the trick.
Nifty little setup for getting 2 hits on the big enemy before GHusk regardless of which pattern you get. After entering the room, wait for the knight to pass the doorframe, jump and pogo, then buffer a dash out of your pogo. This will get you just enough height to get over any small enemies that may be in front of you. Buffer two more pogos out of the dash, and if the big enemy is to the left (first clip) both pogos should hit and you can dash through normally. If the enemy is to the right (second clip), you can do a turnaround slash as you normally would.
Both of these are the same speed as the normal strat for their respective patterns, but getting two hits on the big enemy ensures that it dies to the fireball you shoot when exiting. This should work for any enemy pattern since you can pogo off the decorations in the back if there are no enemies, so you can just autopilot up until deciding whether to turnaround slash.
Inspired by this post, some slash setups for double spike timing. These are based on the timing of the first aspid kill, so they should be more consistent/more accommodating to weird aspid kills than movement-based setups.
I've included two setups. The first is just to buffer 7 slashes following the aspid kill and jump at the same time as the 7th slash (first clip). To avoid bonking the ceiling with your nail, I recommend jumping from the bottom plat at the same time as one of your slashes (4th slash or earlier, any later and you can't make it in time).
The second setup is to jump from the bottom plat at the same time as your 4th slash and just go straight through to the normal setup without waiting (second clip). This is exactly the same timing as the first setup; if you were to continue to do slashes the 7th would line up correctly with the jump. This makes it easier to avoid bonking but also means that missing any of the movement will likely result in you missing double spike too, so ymmv.
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