Where did all my cards go?

Game just crashed with message: 

Error

room.lua:62: attempt to index a nil value

Traceback

room.lua:62: in function 'func'
lib/closure.lua:4: in function 'delay'
room.lua:94: in function 'update'
game.lua:17: in function 'update'
main.lua:104: in function 'update'
[C]: in function 'xpcall'

interesting concept. are the effects procedurally generated or just a huge list? I got to the point where there's like five enemies at a time, but the game crashed. I put the crash report below.

Error: room.lua:62: attempt to index a nil value
stack traceback:
 [string "boot.lua"]:637: in function '__index'
 room.lua:62: in function 'func'
 lib/closure.lua:4: in function 'delay'
 room.lua:94: in function 'update'
 game.lua:17: in function 'update'
 main.lua:104: in function 'update'
 [string "boot.lua"]:509: in function <[string "boot.lua"]:493>
 [C]: in function 'xpcall'