Topic: Hamster and Grub, a tale of SFL and NSFL...
First, the hamster...
There are a few good things about rodent forms. First among them is that hamster, beaver, guinea pig, and the like are mostly differentiated by fur color. Mostly.
As such, if one gains a crapton of weight, loses half of it, and successfully furs one's self out, one will have a pretty good position - with luck on the fur, a little size to the body, and loose, furry skin is the basic motif here.
Filing down all other teeth except the top front will allow one to close one's mouth further than average - it's your teeth keeping them apart - and give one that "they never stop growing" look. Snip the top lip with a pair of pruning shears (sterile, i hope, in a medical setting), letting it completely reheal, then skinning the surface and joining via stitches from the back will give the "rodent upper lip" join - it's a "kitty" without the swoosh and the snipped-in smile - and slicing the nose at a 45-degree angle will give one that snot-nostril'd pigface that a bit of filler can round out.
A human can make a pretty good rodent if their fur growth goes well.
Then, there's the grub for contrast. It, too, requires gaining weight.
Sometimes, profoundly and morbidly obese people can get infections and necrosis in the fold where their neck used to be. It's basically a bedsore-and-mildew situation : it's a deep crease that has been open to the outside, but is under pressure and gets no disinfecting light or oxygen. Soo...
The only possible outcome for this is, erm... "the jabba surgery." ("A jabba of the family hutt," pisses star wars fans off to no end). You're going to have to cut out the infection, the infection covers (and has killed) most of the tissue in the fold, so... there's basically no way to avoid joining the fold. Instead of a neck crease, they now really have no neck.
This lends itself in theory to the grubworm.
Just get some nice silicone or kevlar implants on the eyebrow ridge like this guy...
...go for laser hair removal of almost everything, but hair-club-for-caterpillar in awesome eyebrows going from above the ridge, around and down the back, get your junk removed and converted to an anogenital cloaca in front, amputate the arms, cut the leg skin and fuse the meat, then sonicate everything below the bellybutton that isn't lower spine. Congratulations, a grub is you, and you can just go flopping and oozing your way around while dribbling urine and feces everywhere, right?
Well... no. The grub is NSFL - not just morally on the amount of removal being done, but quite directly. You see, without the help of your arms, our grub will most likely be unable to breathe, and probably won't make it with them.
Back in the dark ages when Rome was still around, most deaths from crucifixion were from running out of the energy required to breathe, and in fact if a straggler held on, someone would come by and break both their legs so they could no longer push themselves up to help with breathing. Consider the position the grub is in - no arms, no legs, face-down on the floor, and obese. They are, frankly, going to suffer the same fate - eventually running out of energy and asphyxiating.
This is too bad; it's a cute little grub, though one certainly would hope to transplant a muscle or two with its nerve bundle to help the incontinence thing. It will not, however, live for more than a few days, just from the breathing thing. Sorry 'bout that.
Whether or not the hamster is safe is subjective - it's still work, though the most irreversible thing is the skin loosening from weight gain. While nothing in life is guaranteed, however, none of these procedures are very likely to kill you.
To breathe ideally, one needs positional change and an absence of weight on the chest - a quadruple amputee would probably asphyxiate without their handlers, and even more so if it was facedown. One also needs the ability to do something about exhaustion and crisis - the ability to push yourself up with your legs in the crucifixion model.
As such, while transitioning into a hamster or beaver is easy (though somewhat extensive), grub and similar styles will likely be invariably lethal. Your arms and legs are as important to breathing as your throat and lungs, and breathing... well, that's important.
Sorry for anyone this disappoints. If "toad" is up your alley, though, having no neck is as simple as obesity and a skin-joining. Maybe a lip-plate for forward projection...
(sadly, my being a mad scientist does sort of bend the content in this forum. Quick, someone make a thread about cute ears and tails...)