Speed is a keyword mechanic found mainly on Ruby troops. A troop with speed can attack or exhaust the same turn that it enters play. Normally a troop must wait until its controller's next turn to attack or exhaust.
Baby Yeti can attack the same turn it enters play. Thus, as a turn 1 play, it can deal 1 damage to an opponent before that player even gets to take a turn if that player is playing second.
- If a troop with speed somehow loses speed before the combat phase, that troop will once again be unable to attack.