Spikes
Spikes are a common obstacle in RTW. They are a miriad of thin spears that come out of the ground on regular intervals, which can be set to loops 1, 2, 3, or 4 (with 1 as fastest and 4 as slower). (These speeds of spikes can go up to 95. Their speed 5+ forms can be implemented by Metatiles.) Any character or monster that touches them in their "up" form will immediately die. They are known to go slightly slower than Electro Tiles and can hit UFOs.