Arcane Spike is the fourth upgrade of Path 1 for the Wizard Monkey in BTD6. It allows the Wizard's magic bolts to deal extra damage to M.O.A.B. Class Bloons, dealing 16 damage per shot to M.O.A.B. Class Bloons. It also pops 5 layers of damage to normal bloons as well, allows the tower to pop Lead Bloons, and attack twice as fast as Arcane Mastery. It costs $8,500 on Easy, $10,000 on Medium, $10,800 on Hard, and $12,000 on Impoppable.
A 4-0-2 Arcane Spike is more effective than the 4-2-0 Arcane Spike because the Arcane Spike upgrade itself has a low pierce, making Intense Magic significantly increase the pierce of the bolts. Additionally, this makes the Intense Magic upgrade better than adding new weapons that don't buff the original energy bolt.
Arcane Spike is fast enough to become maximized by Stronger Stimulant without simultaneously being fast enough to consume all of the strong brew before the duration period ends. This is because it shoots every ~0.275s, compared to 50 shots for the whole 5-second duration that the strong brew would need either of to wear out.
Having a Stronger Stimulant Alchemist nearby a couple of Arcane Spikes target priority can wipe out Round 95 with relative ease.