Collecting a + Clock increases the time limit by a certain number of seconds. + Clocks are generally featured in cyan and green variations. The amount of time replenished by each varies between appearances, although a green + Clock generally replenishes more time than a cyan + Clock.
In Super Mario Bros. Special, the Clock has both a visible minute hand and hour hand, the former pointing to where the 12 would be and the latter pointing to where the 3 would be on a regular clock. As such, the clock appears to show 3:00 as the time. Yoshi's Safari is the first game to feature green + Clocks, and since this appearance, Clocks have since only shown the minute hand, still on the twelve, and three dots placed at where the 3, 6, and 9 would be on a regular Clock respectively. Super Mario Galaxy 2 is the first Super Mario series installment to feature the green + Clocks, but the minute hand was recolored red and the dots are replaced by arrow-like markings.
In Super Mario series
Super Mario Bros. Special
Only one Clock makes an appearance, specifically within World 8-3, where Mario can collect it to add 100 seconds to the timer.
In addition to green + Clocks, there are also cyan ones, which instead refill ten seconds on the time limit while the green ones refill 100 seconds. The icon for the time limit in this game is a + Clock.
Certain courses in the Special Worlds start at only 30 seconds, similar to Super Mario Galaxy 2's Speedy Comet missions. The cyan + Clocks are placed throughout these courses, although some can be collected by defeating certain enemies. Green + Clocks are rare, and one usually only appears in the area following a boss fight, but they can also appear in hidden areas.
Both green and cyan + Clocks make a reappearance, although exclusively in Coin Rush mode. Just as before, the cyan + Clocks add 10 seconds to the timer, but the green clocks instead add 50 seconds.
Both green and cyan + Clocks make another returning appearance, having the same role as in Super Mario 3D Land.
In Yoshi's Safari
A Clock is an item that adds one minute to the player's timer if used during a boss battle, otherwise it contributes earns 6,000 bonus points to their high score.
In Mario vs. Donkey Kong series
They are named Clocks in each of their Mario vs. Donkey Kong appearances.
Clocks sometimes spawn in Donkey Kong levels, and they can be collected by launching a Mini Mario at them. Blue clocks adds 30 seconds to the time limit, although the gray fuming variety takes 30 seconds away.
Aside from Donkey Kong levels, Clocks also appear in minigames. In Donkey Kong levels, Clocks sometimes spawn when the timer falls below 180 seconds. Just as before, collecting a Clock adds 30 seconds to the time limit. In minigames, collecting a Clock instead adds 10 seconds to the time limit.
Several Clocks appear in the levels of Giant Jungle because they have a low time limit and are large in size. A yellow Clock increases the timer by 5 seconds, and a blue one increases it by 20 seconds.
In Super Mario Party
+ Clocks only appear in River Survival mode, in which they are placed along the river. At least most + Clocks to be collected to stop time from running out. The green + Clocks add three seconds to the time limit, which itself is indicated by a "+3" over them, while Hard mode features blue + Clocks, each adding only one second to the timer instead. Time bonuses are also awarded for clearing minigames along the way.
Missions marked with an asterisk (*) are exclusively available while a Prankster Comet is in orbit. Missions marked with two asterisks (**) are only available when receiving a letter from Mailtoad.