Skarners "Crystal Spire" should be a unique item to Skarner that allows him to place it
That way, we won't be enforcing the meta on Skarner to be stuck with the Jungle Role.
Top-lane Skarner can buy a Spire, walk to lane, and either: place it by his turret to have the added security of preventing dives; or he can place it in the middle of the lane so he can gain the buff while laning (but face the risk of having his Spire disabled by the opponent).
Jungle Skarner can buy a Spire, walk into jungle, and either: place his Spire in his own Jungle so he can clear camps efficiently; or put it in the enemy's jungle as he attempts to counter-jungle (while facing the risk of being caught and/or having his Spire disabled by the enemy jungler).
Things to consider:
Should it be a Consumable that is limited to one purchase at a time (like Kalista's Black Spear)?
Should it be a Trinket that can be combined with a Totem/Lens/Orb (like Old Rengar's Bonetooth)?
Should it be a personalized item that can be upgraded with gold (like Viktor's Hex Core)?
And, How many Spires should Skarner be allowed to place on the map at one time?
EDIT - Another idea from the comments: It could also be implemented in a similar way to Azir's Sun Disc, where you'd use your Passive to place the Spire down at a certain location. (Thanks /u/The_Givurr)
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