Yes, they do
It is unfortunate that you believe that your mother is playing "favorites," and, perhaps, she is. Even if that IS the case, there were dozens of different healthy ways to approach your concern. Removing the gas can, yourself (as someone aptly pointed out) is one. Moving out and taking care of your own responsibilities is another (again, suggested in a previous response). But, either of these solutions (along with other more reasonable options) will not mend your choices of behavior. For that, you'll need to implement some difficult behavior readjustments.
The first thing that I would do is to understand that my mother isn't perfect - if she's working all of the time and has tried to raise children (apparently alone as there was no mention of a father), pay bills, and do the best that she could with what skills she had, she's tired and could certainly use some heartfelt (HEARTfelt) help around the house. Then, I would have to put aside my petty, childish, and useless pursuit of proving that my sibling was The Favorite. Sometimes, parents DO favor one child over the other and there is no way to get around that. Yeah, it's unfair (Life is NOT fair), yeah, it might seem cruel (Life CAN be cruel), and yeah, it can fester like an infected wound if we wish it to. So, rather than focusing on feeding the infected wound with my petulant expectations, I would begin to look around and take stock of what I should be grateful for - a roof over my head, food in my mouth, a place that ALLOWS me to have a pet, and so on. Then, I would begin to do things around my mother's house (it is, after all, HER home and I am there only due to her generosity) in PAYMENT for the privilege of not being required to pay rent, utilities, etc. I would begin to seek ways to work WITH my family members rather than pursuing juvenile paybacks.
Maintaining your hatred and jealousy is not going to do anything other than isolate yourself even further. I would be FURIOUS if my son did something deliberately harmful just to prove a point: "I took her outside to "play" and stuck a rag in gas, rung it and scrunched it up so it wasn't dripping and rubbed it on her tail and back." It's not as if someone deliberately poured gasoline onto your dog - it just happened and that's that. But, you took it upon yourself to do something deliberately harmful, vicious, and childish and excused your behavior by saying, "I can't wait for her to come out and realize her dog got into it too and now she has to give her a bath. Maybe now that her night is ruined, she willr get on his ass for it..LOL
"Yep, every time my dog reeks of gas because %¤#&!§-likes to leave gas lying around, Her dog is going to reek of gas." Do you really sit around and dream up new and exciting ways to ruin people's days? Do you really calculate and plan these behaviors as a constant cycle of damage? Is this how you perceive that positive and wonderful things are accomplished in Life?
If this choice of behavior is your modus operandii, you are forcing your mother to choose a favorite by deliberately doing things to cause emotional and physical damage. Perhaps, counseling/therapy (family OR individual) is in order before you choose to do something that you will forever regret.