To get this wait to any of your piñatas get sick, you could also whack a pinata until it gets sick. Then wait until Dastardos get's to your garden, then click the A-button on any Crowla in your garden then direct it to Dastardos and leave the rest of the job to the Crowla.
To get a crowla you can trade it online or get it by having a sour Crowla (Requires Garden level 15) Visit your garden with you having a bottle of medicine and a birdbath in your garden. Then it will become a normal crowla.
Crowla flies / goes to Dastardos and distracts him.
Ping, achievement unlocked. Good luck. ;)