New Defensive Trap- The Sinkhole

The sink hole starts is just like any other trap, when a troop steps on the trap, the ground caves is, dropping the enemy troop to the abyss. The Sinkhole is an upgradable trap that has a 1x1 spacing at lvl 1 and lasts 3 seconds. At lvl 1/2 only small troops can fall into the sinkhole such as archers or barbarians. At lvl 2, the sinkhole does not grow bigger, but is upgraded to last 5 seconds. At lvl 3 the sinkhole will grow to a 2x2 spacing and last for 5 seconds. Once the trap is upgraded to a 2x2, larger troops can fall into the sinkhole such as giants or golems. After that 3-5 seconds the ground grows back over the sinkhole, allowing troops to walk over the ground again. This could help defense a lot, considering it is so hard to defend against OP troops.

Nice idea, but there'd be some logistical problems to work out for a trap to have a different size at different levels. I.e., if you're upgrading it and there isn't room around it, what happens when it upgrades? Also, very possibly the engine for clash of clans doesn't support a defensive structure being different sizes at different levels without lots of work.