Why a dry snail sticks so hard
A snail's foot is a sheet of muscle that grips by suction and mucus, and on a dry surface that grip sets like glue as the moisture at the edge dries. The snail may have wandered out during the night and settled as the surface dried, leaving it firmly fixed and slowly drying out itself. Pulling against that grip puts all the force through the weakest points — the soft foot where it meets the shell, and the thin growing edge of the shell — and either can tear before the suction lets go. The snail is not being stubborn; it is physically bonded to the spot.
Wet, wait, then slide — never pull
Start by wetting around and under the snail with water from its own tank, dripped gently from a spoon so the edge of the foot softens. Give it a few minutes: as the mucus rehydrates the seal weakens, and the snail may simply start moving on its own, which is the best outcome of all. If it stays put, slide a damp, flexible plastic card or a wet fingertip slowly under the foot from one side, working at the pace the snail allows, while your other hand supports the shell so its weight never hangs from the foot. The moment you feel real resistance, stop, add more water and wait again.
Checking for shell and foot damage
Once the snail is free, look it over in good light while it rests on your wet palm. Check the shell's rim for chips or cracks, especially at the growing edge, and watch the foot as it emerges — it should spread flat and smooth, without torn or ragged edges. A snail that retracts fully and comes back out within a few minutes is usually unharmed; one that stays shut and limp after its ordeal needs quiet and observation back in the tank. Note roughly how long it was out, if you know — a snail found in the morning may have been dry for hours.
Back into the water the gentle way
Lower the snail into the tank in your cupped, wet hand or resting on the card, and let it take hold of the glass or a plant at its own pace rather than dropping it and hoping it lands right side up. Place it near cover, not in open water under bright light, and watch that it rights itself and begins to glide. Offer a small piece of its usual food nearby the same day — an eating snail is a recovering snail. Keep handling to this one rescue; repeated lifting for checks does more harm than the original escape.
Stopping the next escape
Escapes are messages: snails leave water that does not suit them, or follow a waterline up and over a rim with a gap in the lid. Check the usual drivers — poor water quality, too little food, aggressive tankmates, a climbing route up a filter outflow. Fit a lid or mesh over gaps around pipes and cables, and lower the waterline slightly if the rim is easy to cross. A snail found wandering the glass above the waterline in the evening is worth watching, because that is the rehearsal for the real escape. If damage turns up that you cannot judge confidently, put a follow-up question to KinsLe's Kimmy; she answers using the KinsLe Answers library.