Killer ideaS - the Blight
There are special flowers spawn around a map. Both Killer & Survivor can collect flowers.
Survivor:
A Survivor collect a flower gets a token. Each token get 3% debuff on interaction. 3 token will get broken permanently, survivors can no more collect flower.
Killers:
Power: Killer has 100% speed. Killer collect a flower will get 1 token. Each token gain 5% speed.
Killer starts with 2 tokens, which mean he can dropped to 90% speed
He can gain up to 125% speed (7 token max).
3 flower spawn at the start. A flower spawn every 45sec. Maximum 5 flower can spawn at a time.
Alternate attack: can aim on the ground (like Freddy snare) and pull up an attack (plant spike up from the ground). The attack area is 4m radius, takes 1.5sec for the spike to grow (like PH's alternate attack). Requires a token
Ability idea 1: Killer can use a token to lay a flower-trap (lose 5% speed), survivor run pass the trap will get 1 token, then the trap is destroyed. Survivors scream if contact with the trap. Trap can not be disarmed.
Ability idea 2: Killer can use a token to lay a flower-trap (lose 5% speed), survivor run pass the trap will trapped and require wiggle for 10sec to escape, then the trap destroyed. Leave no damage. Trap can not be disarmed
Ability idea 3: Killer can use a token (lose 5% speed) to plant a big plant which become an obstacle that blocking movement. Survivor can remove the obstacle in 15sec
I dont disappoint on the newest Killer's idea. But I disappointed that they could make a Plant theme Killer.

Comments
Bump
I'm confused, you say both Survivor and Killer can collect flowers, but then describe the survivor collecting them negatively affecting them? Also how would collecting the flowers work, because depending on that this killer could be the strongest or weakest in the game, as with 0 tokens he'd be slower than nurse with no power, and with 7 tokens he'd be barely slower than Legion is during frenzy.
My blight isnt relate to Devs' blight.
Killer is very slow at the start. Force him to collect flowers. Survivor collect flowers to prevent Killer getting stronger, at the cost of 3% debuff on any interaction (Gen, healing ect)
The game can go in ways like this:
Survivors can take 2 flowers each. But if they step on his flower traps cause them to exposed the rest of the game.