These towers should fit into the medieval theme, but should not be too similar to the existing ones.
After some thinking, I came up with the 'Civil defense tower':
Kingdom rush 2: Civil defense tower
Although the civil defense tower reloads very slow and its range is lower than all other towers’, it deals area damage and ignores both armor and magic resistance. Civilians use buckets to throw everything that is available to them on the enemies, from household waste to acid, creating damaging pools on the ground that disappear after a few seconds.
Basic towers
Level 1: Civil defense (price: 100 gold, reload: very slow, range: very short)
Level 2: Hot water (price: 160 gold, reload: very slow, range: very short)
Level 3: Burning oil (price: 240 gold, reload: very slow, range: very short)
Advanced towers (level 4)
Alchemists’ lab (price: 300 gold, reload: very slow, range: short)
Philosopher’s stone (turns enemies into solid gold, making them temporarily immobile)
Panacea (cures all diseases of allied soldiers in range, making them regenerate health faster)
Witches’ caldron (price: 300 gold, reload: very slow, range: short)
Acid overflow (acid floods from the caldron to poison every enemy in range)
Acid vapor (acid vapor from the caldron deals poison damage to nearby flying enemies)
Damage of all towers and special abilities to be decided upon testing and revising, to make sure it’s well balanced relative to the other tower types.
I would love to hear what others think about this and if you need some fail artwork of the towers, don't be shy to ask x]