Something like this probably will help you:
public T dosomething<T>(object o)
{
T enumVal= (T)Enum.Parse(typeof(T), o.ToString());
return enumVal;
}
But this will work only with enums, for clear reason of using Enum.Parse(..)
And use this like, for example:
object o = 4;
dosomething<Crustaceans>(o);
That will return Toad
in your case.