Ice Tortoise

Hardmode, the ice biome, no summon involved. It gives off a fair amount of light, which is unusual for something this dangerous and works entirely in your favor. You will see the glow around a corner before you see the tortoise, and the same light doubles as a way to read the shape of caves you have not explored. The jungle has a functionally identical version in the Giant Tortoise, so everything here applies there too. Both look like a nod to the Tatori from Super Metroid, which pulled the same trick of tucking in and flying at you.

Left alone it plods. The attack is the other mode: it pulls into its shell, becomes much harder to hurt, and launches itself at you. The line is locked in the instant it retracts, based on where you were standing then, so moving after it commits usually beats it. It is not completely blind afterward though. Once it is above you it will slow hard and try to drop onto your head, so a single sidestep is not always enough.

This is the part that decides the fight. Standing close, the wait between spins is long and you will often see none at all. Give it a clear line across a cavern and that wait collapses to almost nothing, and it hurls itself at you over and over. Backing away from a tortoise makes it more dangerous, which is the opposite of what the animation suggests. Walk toward it.

Any hit cancels a spin in progress and resets the timer, so a weapon with a high rate of fire means it never completes one. A Megashark, a yoyo or a fast summon holds it in that state indefinitely. The wind up is short, so with something slow you need to already be swinging when it tucks in rather than reacting to it.

• Water is the worst place to fight one. If a spin ends in liquid it goes straight into another with no pause at all, so drain the pool or move the fight somewhere dry.
• It cannot drop through platforms. A few long rows above the cave floor take the vertical threat away completely and let you shoot down at it.
• It is much harder to hurt while it is shelled and spinning, so the damage you land between attacks is worth more than the damage you land during one.