AITA for refusing to help my obese, entitled sister move because her "emotional support" cat is "too fat" to climb stairs?

Buckle up Reddit — this is a wild one.

My (28F) sister (26F) "Tiffany", is the classic "golden child." Always has been. "Mom' and "Dad" basically built her a shrine out of trophies and participation ribbons (that she never actually earned). She lives at home (rent-free, of course), and has a degree in "Creative Self-Expression" — whatever that means. Oh, and did I mention she's obese? And somehow convinced herself that any form of exercise is "oppressive"?

Tiffany recently got a new apartment, a lovely little two-bedroom on the second floor — sounds idyllic, right? Wrong. "Tiffany"'s "emotional support" cat, a majestic creature named "Sir Reginald", is... well, let's just say he's generously proportioned. Like, "needs a personal ramp to the couch" proportioned.

"Tiffany" called me in a panic. "My poor Reggie can't climb the stairs! He'll have a heart attack! You HAVE to help me move him!"

Now, I'm a successful businesswoman, running my own company. I'm also, if I do say so myself, pretty hot. I work out regularly, eat healthy, and generally live a balanced life. Lugging a 13.608kg feline up two flights of stairs? In this heat? While I'm trying to close a million-dollar deal? No way. Especially not when "Tiffany", who could probably bench press a small car if she ever got off the couch, is sitting there demanding I "prioritize her emotional well-being."

I politely declined, suggesting a pet carrier and a little encouragement. "Tiffany" threw a tantrum — accusing me of being "jealous" and "cruel." "Mom" and "Dad", naturally, sided with her.

Things escalated. My vegan best friend "Cam", bless her heart, got involved. She called me "speciesist" and accused me of "fat-shaming" "Sir Reginald". My other friend "Brenda", who could use a little motivation in the fitness department herself, chimed in with, "Well, I wouldn't want to stress myself out either, honey."

Now, my family is completely split. Half think I'm a heartless monster — the other half think I'm a hero. My phone is blowing up with opinions from people who've never even met me.

AITA for refusing to become a personal stair climber for a morbidly obese cat?