This revised art depicts one pony getting the virus. The card's info says:
The Great Rainbow Weight Gain Virus
Normal Trap
Tribute 1 "My Chubbier Pony" or "My Chubbiest Pony" monster. Destroy all monsters your opponent controls whose ATK is less than or equal to the Tributed monster's DEF, then check your opponent's hand and all cards they draw for 3 of their turns and destroy all monsters with less ATK than the Tributed monster's DEF. Monsters still on the field after this effect get 1 "Weight Gain Counter" during those 3 turns and lose 400 ATK for each counter.
Super Rare