“Just sitting here… being adorably mushroom-cat happy birthday!” – Funny Adult Square Birthday Card for 18+ with Matching Envelope – Perfect for Adults Only

Looking for a delightfully silly way to celebrate a birthday? This 18+ card is perfect for adult humor lovers! Featuring a cheeky mushroom-cat design and playful quote, it’s guaranteed to deliver laughs, smiles, and a little birthday mischief.

Card Features:

• Square card with matching square envelope
• Envelope features a blue inner lining for an extra pop of fun
• Printed on high-quality cardstock
• Blank inside for your personal message
• Perfect for adult friends, family, or anyone who loves a little quirky humor

Customisation Options:

You can add your own personalized twist to the card:

• Add a custom quote at the top or bottom (max 10 words)
• Add quotes to both top and bottom (max 20 words total)
• Or select No Change to keep the original funny quote: "Just sitting here… being adorably mushroom-cat happy birthday!”

Don’t forget to leave your custom quotes in the order notes at checkout if you’re choosing a personalized option.

18+ only – Contains adult humor and is intended for mature buyers.

Celebrate a birthday the mushroom-cat way — silly, quirky, and unforgettable!