Setup was inspired by 谔虺's version of this
True harmless
This isn't very stable harmlessly due to a variety of reasons but it's mainly due to low dps and hypno-shroom being trash. You can definitely get this to work endlessly if you turn off the harmless mode though.
Sequence: Ice + Doom | Imitator Ice + Cherry Squash Hypno
The cherry and squash are fine but the squash is risky against jacks if timed wrong (like I do)
Hypno can't always kill the footballs. If there's a crowd of 5 footballs on one row, it's not gonna kill them. Luckily, the footballs that need to be killed will be frozen so it gives the hypnotized football a chance to deal damage, plus the winter-melons are constantly dealing damage so the odds are in your favor. You can also choose which row you hypnotize which is what I was doing in the video which makes it work 99% of the time but not always.
Even if the footballs don't die, you can stall with blover (not affected by harmless mod) and hope they die to the melons.
It's difficult to find a place to put the imitator ice. I guarantee there will always be a place to put it but sometimes you have to wait until the doom blows up.
Also, from my testing, this works against slowed imps only. If the imps are unslowed, they can very easily get through. At 10:20, one imp almost got through but it died to my ice damage.
Sun-
I gained 200 sun which means you can replace a twin for a melon but 6 twins looks cooler and works
Reference: www.bilibili.com/video/BV19P4...
The gameplay in this vid was completely different from mine though