With only concern for your feet in mind, you rush straight to you kitchen and grab the sharpest knife you can find. Worried that you might cut your feet, you try to carve at a lower point on the shoe and put the knife just above the sole. Starting at the middle of the left side, you slowly bring the knife forward... then you carefully pull it across to the right... then back...
SPRANG!
A sound bursts out like a loaded spring and the knife is knocked from your hand in an instant as a flash of brown explodes from the now-open front of your shoe. Almost in tandem, the pressure becomes too much for your other shoe to bear and its front rips open without even the slightest bit of coaxing from that knife of yours, another brown blur shooting from the end of it. You're so surprised by the sudden foot explosions that you fall over backwards, almost managing a full somersault in reverse before you finally stop yourself and sit up to try and figure out what, exactly, just happened. Fortunately enough (or unfortunately, given the circumstances), doing just that only takes a few seconds.
From the open ends of your shoes, there now extend two long brown feet, at least twice the length of your human ones. At their "toes" they turn black, small claws on each of them, with three toes per foot. Overall, they seem to have a somewhat exaggerated and unrealistic look, like a cartoon character or costume. Then again, given the fact that they're apparently made of latex, their looking like a costume isn't that odd. What is odd, on the other hand, is how they FEEL - whereas you'd thought at first that the stuff in your shoes had just covered your feet, you can feel sensations all along these things. You can feel the air touching them, feel the ground beneath them, feel the tattered footwear still hanging uselessly on half of them. It's all muted, but the sensation is still there. Attempting to wriggle your toes, you find that you have limited success as the puffy kangaroo digits wriggle slightly. Finally, you attempt to stand, and (surprisingly enough) find that these feet, despite their apparent latex composition, are incredibly sturdy. In fact, while their surfaces are soft and probably couldn't support your weight on their own, you can feel a more solid core just beneath that, one that easily matches your own feet. But then, it's looking like these ARE your own feet now, so that only makes sense.
...No, wait, nothing here makes sense! Your shoes just exploded to accommodate a pair of KANGAROO FEET! Panic over your situation starting to finally set in, you begin to think hard. How the heck can you fix this?!?