91 - Warp letter

Edit Objects Dialog Box
Logic: CoveredPowerup or InGameIcon
Image Set: GAME_WAPWORLDONLY_TRIGGER or alwayz GAME_INGAMEICONZ_ +
SECRETA
Smarts: 0 (default) Tile 1 or 9 selected;
or Clear Tile (1 through 301) to replace the
Rock or Hole/Mound when broken/dug up.
Objectz on an Arrow Tile may never be acquired!
0 (default ... not used)
Powerup: 91 0 (default ... not used)
One of the four letterz.

These may sometimez be acquired via a SecretTeleporterTrigger which generatez a Red Warp (RW) or via a Secret Switch , which temporarily changez Tilez, allowing a Grunt to bypass an otherwise impossible barrier.