Reindeer Bells

The Ice Queen drops it, and only from wave fifteen of the Frost Moon onward. That means a working Frost Moon arena and enough damage to push deep into the event over and over, which in practice puts it well past Plantera. It is a lot of setup for a mount, and most players end up with it long after they stopped needing the mobility.

Rudolph runs, and then he flies, and the flight is not a short hop. Hold jump to climb, and add the down key to cap your altitude so you travel flat instead of drifting into the sky, the same control trick the Hoverboard uses. Angle matters more than you would expect: pushing sideways while you climb gets you much higher than holding straight up, because the flight timer stretches with your horizontal speed.

Fall damage does not exist while the buff is up, so ending a flight by simply dropping off the mountain is fine.

Ground speed. Most wings solve getting airborne and do nothing for you on foot, while this is quick in both modes and stacks on top of the movement accessories you already have rather than overriding them. There is a wind-up of a couple of seconds before you hit top speed, so it pays off on long crossings more than on short hops, and in open air it will outrun most things chasing you.

Asphalt is the one surface where you are better off on foot, since the runway boost does not carry over while mounted. The workaround, if you care, is to build up speed on the asphalt unmounted, slide onto frozen slime blocks, and mount there. Pressure plates still trigger normally underneath you. The nose throws a small light, not enough to explore by but enough to see the next ledge. Sit still long enough and Rudolph starts grazing.

This was the first mount added to the game. Along with the minecart, it is one of only two that exist on every platform.