Frost Shield

Frost Shield is earned from defeating Blizzard Buffalo. Its normal mode is a dart of ice that delays before firing (good for setting traps). If it hits a wall or a floor, it turns into an ice spike trap. The charged mode is probably where the "shield" comes in, as a big spiked block of ice appears on X's hand. Note: If used underwater, it becomes a large block of ice that X can ride on.