Pump air into a rubber balloon and watch the physics that a spring model can't show: real rubber follows a neo-Hookean stress-strain law, so the pressure needed to keep inflating rises, peaks, actually falls back down through an easier middle stretch, then climbs sharply again as the material nears its elastic limit and bursts. This 2D canvas simulator plots that exact pressure-vs-stretch curve live as you blow, alongside a growing balloon that pops when the wall's finite extensibility runs out. Tune wall thickness, rubber stiffness, the elasticity limit and your own blow strength to see how each one reshapes the curve — and whether you can blow hard enough to pop it yourself, or get stuck at a stable equilibrium instead.