It is not possible to add instance variables to individual tiles. There are several other ways you can achieve this.
1. You can create another tilemap with the same size. In this tilemap define only a few tiles - for example, tile #1 red which will mean dangerous, tile #2 green is walkable, tile #3 blue is water etc. Make this tilemap invisible and place it on top of your main tilemap.
When player is moving, check tile number under the player on this second tilemap. If tile id is 1, then kill the player.
2. If you have many dangerous tile types (spikes/lava/swamp), add their IDs into an array "DangerousTilesArray". When player steps on a tile, check if this tile ID is in the array, then kill the player. You can create similar arrays for other types of tiles, for example "TreasureTiles", "SlowdownTiles".
3. Similar to previous method, but instead of arrays you can use text global variables. Simply create a variable with the list of tiles:
Then check if tile ID is in this list using find() expression.