過硬

过 = 寸 + 辶 : Gitta Giraffe is trying out her new gladiator sandals in the observatory's bathroom. She's even able to cross a puddle of water with them by just walking on the water, so thumbs up for her!

硬 = 更 + 石 : Maud Younger (y) finds the snake which ate too much (更) in the engine's bathroom ((e)ng4), and it feels miserable. To make the snake feel better Maud massages the snake using two warm stones (石). As Maud massages the snakebshe finds that the snake's belly is really hard (硬).