public void FusionCheck()
    {
        if (Input.GetMouseButtonUp(0))
        {
            firstPositionSet     = false;
            onlyOneFollowUnitNum = false;
            followingMouse       = false;
        }

        if (Input.GetMouseButtonUp(0) && mouseCheck)
        {
            bool unitNumCheck = (fusionManager.GetFollowingUnitNum() == 0);

            onlyOneFollowUnitNum = false;

            if (!unitNumCheck)
            {
                fusionManager.SetFollowingUnitNum(0);
                followingCheck = false;
            }
            if (shortestScript != null)
            {
                if (shortestScript.unitId == unitId)
                {
                    if (shortestDistance < firstUnitClickableRange && gameManager.GetMoney() >= levelUpCost)
                    {
                        if (!shortestScript.isDead)
                        {
                            LevelUp(shortestScript.unitId, unitLev, shortestScript.unitLev);
                        }
                    }
                    else if (gameManager.GetMoney() < levelUpCost)
                    {
                        Instantiate(stageManager.notEnoughMoneyText, stageManager.textSpawnPosition);
                    }
                    else if (unitLev >= gameManager.GetSaveData().maxFusionLev)
                    {
                        Instantiate(stageManager.maxLevelText, stageManager.textSpawnPosition);
                    }
                }
            }

            ComeBack();

            mouseCheck = false;
        }
        else if (shortestScript != null)
        {
            if (followingMouse && shortestDistance < firstUnitClickableRange && unitId == shortestScript.GetUnitID() && unitLev == shortestScript.GetUnitLev())
            {
                if (unitLev >= gameManager.GetSaveData().maxFusionLev)
                {
                    costText.text = "이미 최대레벨입니다.";
                    return;
                }
                costText.text = $"{levelUpCost} 원";
            }
            else
            {
                costText.text = "";
            }
        }
        else
        {
            costText.text = "";
        }
    }