This would be a physical change due to the fact that you are changing the state of matter of the ice cream cone. The physical state of matter can be reversed by refreezing the melted ice cream.
The intense heat of a fire would turn the marshmallow into ash, making this a chemical change. This is also an irreversible effect because you cannot turn ash back into marshmallow.
A person turned completely into stone would be a chemical change because their chemical composition has been altered. Unfortunately for them, the change would be irreversible.
Physical changes - reversible - appearance
Chemical changes - Irreversible - Chem composition
We can tell physical and chemical changes apart due to the fact that physical changes are reversible while chemical changes are irreversible. We can also tell them apart because physical changes alter the physical appearance of the object while chemical changes change the chemical composition. Let me show you a few examples of physical and chemical changes!