I managed to do the animation part, but I still don't like it. (If possible, could anyone teach me how to make it that when e is not pressed anymore, the animation stops? I followed a crawl tutorial and I can barely understand what's going on here. I want to learn lua, but all I know is very basic Java)

leaning = false
local humanoid = script.Parent.Humanoid
crawlAnim = nil
crawlAnimIdle = nil
game:GetService("UserInputService").InputBegan:connect(function(input)
	if input.KeyCode == Enum.KeyCode.E then
		if leaning == true then
			leaning = false
			crawlAnim:Stop()
			crawlAnim:Destroy()
			crawlAnimIdle:Stop()
			crawlAnimIdle:Destroy()
			humanoid.WalkSpeed = humanoid.WalkSpeed*2
		else
			leaning = true
			crawlAnim = humanoid:LoadAnimation(script.CrawlAnim)
			crawlAnimIdle = humanoid:LoadAnimation(script.CrawlAnimIdle)
			humanoid.WalkSpeed = humanoid.WalkSpeed/2
		end
	end
end)

while wait()do
	if leaning == true then
		crawlAnim:AdjustSpeed(humanoid.WalkSpeed/4)
		if humanoid.MoveDirection ~= Vector3.new(0,0,0)then
			if crawlAnim.IsPlaying ~= true then
				crawlAnim:Play()
			end
		else
			crawlAnim:Stop()
			crawlAnimIdle:Play()
		end
	end
end
Anonymous