Here's the lyrics and my translation.

I'm unsure about what これ in the second last verse refers to:

僕らは忘れてる あの時使ったはずの魔法


Is it the teddy bear? Like it was referred to as 彼 earlier when she was young but became a これ when she grew up to show she lost her childhood dreams?

Or am I off on a tangent ... Any ideas?