|"You belong in a museum!"
A Siege Rider Minion was an advanced minion that resulted from casting the non-dominion version of the summoner spell Promote on any nearby minion. It was removed from gameplay along with Promote due to balancing issues where several players in a team would simultaneously Promote regular minions into those Siege Rider Minions in a single lane, granting them enormous pushing power in that lane. These minions are confirmed to be removed, as Promote and Banner of Command now turn super minions into Anti-turret cannons in Dominion and Summoner's Rift respectively.
The purple siege rider minion is holding a rally banner which is also known as Rally.