Spring Rabbit

Not hard to obtain one.
A bit boring if you doing it not in the first days, because eggs spawn at a rate proportional to farm rate. The more ppl farm them, the more eggs spawn.
Also probably dropped from eggs.
(However, it's only available during event period.)

The Spring Rabbit comes from a [item=44794] which is contained in a Brightly Colored Egg. The Eggs are located around starter zones. You can only obtain the Brightly Colored Eggs during the World Event Noblegarden. It also cost 100 Noblegarden Chocolate. The Chocolates can be found inside the Brightly Colored Eggs. There is a Noblegarden Vendor at each zone where you can get the Brightly Colored Eggs. The Noblegarden event takes place in April around Easter. The rabbit also leaps after you if he strays too far and when your Spring Rabbit finds another Spring Rabbit, they call in love and make baby Spring Rabbits.

Just noticed that when you have it out and walk near someone else who has one, hearts appear over their heads.
They hop towards each other and will chase each other around for a bit, and then a tiny egg pops out onto flowers, which hatches into a baby rabbit.