>>54261781it'd probably depend on the transformation method, the most likely thing is that it'd feel alien, perhaps a bit tingley, the different new sensations of weight/height, having different appendages (stumps, extra hands, fins, wings, tails, etc), center of gravity, balance, strength, perception, would be different, your five senses would probably work a bit different as well not to mention certain instincts/subconscious stuff like walking/breathing (things that would just automatically click) which would most likely include any new powers you might've been granted (like flying, water breathing and possibly attacks though some would require training by pokemon logic) my guess is it'd feel natural but strange to your human mind to comprehend but not painful, like the feeling of trying something new for the first time which could be pleasant or not depending on your sensibilities.
like a magic "poof" would be the most alien, while something like a slow burn or ring portal would give you a moment to acclimate to changes, though being half way though a TF probably would be alien too.