If there are too many properties (columns) for each creature in the array, it will be difficult to work with them, because you'll have to reference them by index.
I would probably choose a third option - JSON. JSON takes some time to learn, but if you organize the data structure correctly, it should be the easiest and most convenient option.
Here is an example:
{
"ratata":
{
"Name": "Ratata",
"Element": "Earth",
"Level": 4,
"Strength": 3,
"Speed": 3,
"Armor": 2,
"HP": 21,
"Vulnerabilities": "Dark,Poison",
"attacks": [{ "Kick": 3}, { "Punch": 1}]
},
"ekans":
{
"Name": "Ekans",
"Element": "Poison",
.........
}
}