The 42-year-old supermodel playfully nudged boyfriend Vito Schnabel to buy the luxury snail for her at the seventh annual Milan amfAR auction in Milan, Italy, last night.
Heidi hosted the event, which raised money for AIDS research, and ensured her art curator partner did his part for charity.
Speaking from the stage, Heidi jokingly said: "Vito, I thought you were going to buy me the snail!"
Vito, 29, shelled out $22,000 for the plastic accessory, which was designed by Cracking Art Group.
Heidi plans to put her new snail on display in her garden, reports the New York Post newspaper.
Heidi and Vito have been getting serious over the last several months and it's thought the 'Project Runway' star is even eager to become Vito's wife.
A source previously said: "Heidi is obsessed with him.
"She's totally serious about marrying him.
"She says he's an old soul and great with the kids, so why not make it official.
"No one will be surprised if they're engaged soon ... Heidi has never been good at being alone."