Balloon

Use
The Green balloon, when equipped, increases your jump height. You can click to increase the balloon's size, which gives you an even greater jump height. You can blow up the balloon 5 times, on the 5th time it allows you to fly up infinitely. If you attempt to blow it up a 6th time, however, it will blow up and send you down. The green balloon causes damage to blocks and it can also be used for movement.

How to receive it.
It is sold at The Warehouse for 2500 at level 3.