Can I reference a Sprite's number or name?

[ego-lay_atman-bay]

@bluebaritone21

Also, how do I type upvars in snapblocks?

Just use 2 parentheses around the variable name.

script variables ((a)) @addInput

script variables ((a)) @addInput

You can learn more about snapblocks at https://snap-blocks.github.io/docs/syntax or How to write snapblocks