This is what a "spike" looks like in Cattleyas. It's like a protective "bag" and what more or less resembles a spike is growing inside. As it grows, it will break up the "bag" and comes out.
We call this "bag" a sheath.
Some Catts bloom from green sheaths while others do it from dry ones.
Let me add one more thing. The presence of a sheath doesn't
necessarily mean that the plant will bloom. Sometimes the blooms inside don't develop. That's what is called an empty sheath.