Why can't we make a radioactive spider which if bites us changes us into spiderman ??

Dear student. First of all this ask n answer forum is only for asking academic related question . But for your curiosity I would like to give answer to your question is that if radioactive elements enters once inside the body, the radioactive isotope will ionize the cells around it sometimes causing irreparable damage. Radioactive isotopes migrate in the body in the same way as inert isotopes of the same element. In large enough doses, these isotopes will cause cancer and other diseases. Regards